diff --git a/makefile b/makefile
index 43c7cae..06f7d18 100644
--- a/makefile
+++ b/makefile
@@ -57,8 +57,8 @@ raylib:
 raylua_s: src/raylua_s.o $(EXTERNAL_FILES) libraylua.a
 	$(CC) -o $@ $^ $(LDFLAGS) luajit/src/libluajit.a
 
-raylua_e: src/raylua_e.o src/raylua_self.o src/raylua_builder.o src/lib/miniz.o \
-		$(EXTERNAL_FILES) libraylua.a
+raylua_e: src/raylua_e.o src/raylua_self.o src/raylua_builder.o \
+		src/raylua_builder_ui.o src/lib/miniz.o $(EXTERNAL_FILES) libraylua.a
 	$(CC) -o $@ $^ $(LDFLAGS) luajit/src/libluajit.a
 
 src/res/icon.res: src/res/icon.rc
@@ -89,7 +89,7 @@ src/autogen/builder.c: src/raylua_builder.lua
 clean:
 	rm -rf raylua_s raylua_e libraylua.a src/raylua_e.o src/raylua_s.o \
 		src/raylua.o src/raylua_self.o src/raylua_builder.o src/autogen/*.c \
-		src/lib/miniz.o src/res/icon.res
+		src/raylua_builder_ui.o src/lib/miniz.o src/res/icon.res
 	$(MAKE) -C luajit clean
 	$(MAKE) -C raylib/src clean
 	rm -f raylib/libraylib.a
diff --git a/src/lib/microui.c b/src/lib/microui.c
new file mode 100644
index 0000000..a8a3f74
--- /dev/null
+++ b/src/lib/microui.c
@@ -0,0 +1,1208 @@
+/*
+** Copyright (c) 2020 rxi
+**
+** Permission is hereby granted, free of charge, to any person obtaining a copy
+** of this software and associated documentation files (the "Software"), to
+** deal in the Software without restriction, including without limitation the
+** rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+** sell copies of the Software, and to permit persons to whom the Software is
+** furnished to do so, subject to the following conditions:
+**
+** The above copyright notice and this permission notice shall be included in
+** all copies or substantial portions of the Software.
+**
+** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+** FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+** IN THE SOFTWARE.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "microui.h"
+
+#define unused(x) ((void) (x))
+
+#define expect(x) do {                                               \
+    if (!(x)) {                                                      \
+      fprintf(stderr, "Fatal error: %s:%d: assertion '%s' failed\n", \
+        __FILE__, __LINE__, #x);                                     \
+      abort();                                                       \
+    }                                                                \
+  } while (0)
+
+#define push(stk, val) do {                                                 \
+    expect((stk).idx < (int) (sizeof((stk).items) / sizeof(*(stk).items))); \
+    (stk).items[(stk).idx] = (val);                                         \
+    (stk).idx++; /* incremented after incase `val` uses this value */       \
+  } while (0)
+
+#define pop(stk) do {      \
+    expect((stk).idx > 0); \
+    (stk).idx--;           \
+  } while (0)
+
+
+static mu_Rect unclipped_rect = { 0, 0, 0x1000000, 0x1000000 };
+
+static mu_Style default_style = {
+  /* font | size | padding | spacing | indent */
+  NULL, { 68, 10 }, 5, 4, 24,
+  /* title_height | scrollbar_size | thumb_size */
+  24, 12, 8,
+  {
+    { 230, 230, 230, 255 }, /* MU_COLOR_TEXT */
+    { 25,  25,  25,  255 }, /* MU_COLOR_BORDER */
+    { 50,  50,  50,  255 }, /* MU_COLOR_WINDOWBG */
+    { 25,  25,  25,  255 }, /* MU_COLOR_TITLEBG */
+    { 240, 240, 240, 255 }, /* MU_COLOR_TITLETEXT */
+    { 0,   0,   0,   0   }, /* MU_COLOR_PANELBG */
+    { 75,  75,  75,  255 }, /* MU_COLOR_BUTTON */
+    { 95,  95,  95,  255 }, /* MU_COLOR_BUTTONHOVER */
+    { 115, 115, 115, 255 }, /* MU_COLOR_BUTTONFOCUS */
+    { 30,  30,  30,  255 }, /* MU_COLOR_BASE */
+    { 35,  35,  35,  255 }, /* MU_COLOR_BASEHOVER */
+    { 40,  40,  40,  255 }, /* MU_COLOR_BASEFOCUS */
+    { 43,  43,  43,  255 }, /* MU_COLOR_SCROLLBASE */
+    { 30,  30,  30,  255 }  /* MU_COLOR_SCROLLTHUMB */
+  }
+};
+
+
+mu_Vec2 mu_vec2(int x, int y) {
+  mu_Vec2 res;
+  res.x = x; res.y = y;
+  return res;
+}
+
+
+mu_Rect mu_rect(int x, int y, int w, int h) {
+  mu_Rect res;
+  res.x = x; res.y = y; res.w = w; res.h = h;
+  return res;
+}
+
+
+mu_Color mu_color(int r, int g, int b, int a) {
+  mu_Color res;
+  res.r = r; res.g = g; res.b = b; res.a = a;
+  return res;
+}
+
+
+static mu_Rect expand_rect(mu_Rect rect, int n) {
+  return mu_rect(rect.x - n, rect.y - n, rect.w + n * 2, rect.h + n * 2);
+}
+
+
+static mu_Rect intersect_rects(mu_Rect r1, mu_Rect r2) {
+  int x1 = mu_max(r1.x, r2.x);
+  int y1 = mu_max(r1.y, r2.y);
+  int x2 = mu_min(r1.x + r1.w, r2.x + r2.w);
+  int y2 = mu_min(r1.y + r1.h, r2.y + r2.h);
+  if (x2 < x1) { x2 = x1; }
+  if (y2 < y1) { y2 = y1; }
+  return mu_rect(x1, y1, x2 - x1, y2 - y1);
+}
+
+
+static int rect_overlaps_vec2(mu_Rect r, mu_Vec2 p) {
+  return p.x >= r.x && p.x < r.x + r.w && p.y >= r.y && p.y < r.y + r.h;
+}
+
+
+static void draw_frame(mu_Context *ctx, mu_Rect rect, int colorid) {
+  mu_draw_rect(ctx, rect, ctx->style->colors[colorid]);
+  if (colorid == MU_COLOR_SCROLLBASE  ||
+      colorid == MU_COLOR_SCROLLTHUMB ||
+      colorid == MU_COLOR_TITLEBG) { return; }
+  /* draw border */
+  if (ctx->style->colors[MU_COLOR_BORDER].a) {
+    mu_draw_box(ctx, expand_rect(rect, 1), ctx->style->colors[MU_COLOR_BORDER]);
+  }
+}
+
+
+void mu_init(mu_Context *ctx) {
+  memset(ctx, 0, sizeof(*ctx));
+  ctx->draw_frame = draw_frame;
+  ctx->_style = default_style;
+  ctx->style = &ctx->_style;
+}
+
+
+void mu_begin(mu_Context *ctx) {
+  expect(ctx->text_width && ctx->text_height);
+  ctx->command_list.idx = 0;
+  ctx->root_list.idx = 0;
+  ctx->scroll_target = NULL;
+  ctx->hover_root = ctx->next_hover_root;
+  ctx->next_hover_root = NULL;
+  ctx->mouse_delta.x = ctx->mouse_pos.x - ctx->last_mouse_pos.x;
+  ctx->mouse_delta.y = ctx->mouse_pos.y - ctx->last_mouse_pos.y;
+  ctx->frame++;
+}
+
+
+static int compare_zindex(const void *a, const void *b) {
+  return (*(mu_Container**) a)->zindex - (*(mu_Container**) b)->zindex;
+}
+
+
+void mu_end(mu_Context *ctx) {
+  int i, n;
+  /* check stacks */
+  expect(ctx->container_stack.idx == 0);
+  expect(ctx->clip_stack.idx      == 0);
+  expect(ctx->id_stack.idx        == 0);
+  expect(ctx->layout_stack.idx    == 0);
+
+  /* handle scroll input */
+  if (ctx->scroll_target) {
+    ctx->scroll_target->scroll.x += ctx->scroll_delta.x;
+    ctx->scroll_target->scroll.y += ctx->scroll_delta.y;
+  }
+
+  /* unset focus if focus id was not touched this frame */
+  if (!ctx->updated_focus) { ctx->focus = 0; }
+  ctx->updated_focus = 0;
+
+  /* bring hover root to front if mouse was pressed */
+  if (ctx->mouse_pressed && ctx->next_hover_root &&
+      ctx->next_hover_root->zindex < ctx->last_zindex &&
+      ctx->next_hover_root->zindex >= 0
+  ) {
+    mu_bring_to_front(ctx, ctx->next_hover_root);
+  }
+
+  /* reset input state */
+  ctx->key_pressed = 0;
+  ctx->input_text[0] = '\0';
+  ctx->mouse_pressed = 0;
+  ctx->scroll_delta = mu_vec2(0, 0);
+  ctx->last_mouse_pos = ctx->mouse_pos;
+
+  /* sort root containers by zindex */
+  n = ctx->root_list.idx;
+  qsort(ctx->root_list.items, n, sizeof(mu_Container*), compare_zindex);
+
+  /* set root container jump commands */
+  for (i = 0; i < n; i++) {
+    mu_Container *cnt = ctx->root_list.items[i];
+    /* if this is the first container then make the first command jump to it.
+    ** otherwise set the previous container's tail to jump to this one */
+    if (i == 0) {
+      mu_Command *cmd = (mu_Command*) ctx->command_list.items;
+      cmd->jump.dst = (char*) cnt->head + sizeof(mu_JumpCommand);
+    } else {
+      mu_Container *prev = ctx->root_list.items[i - 1];
+      prev->tail->jump.dst = (char*) cnt->head + sizeof(mu_JumpCommand);
+    }
+    /* make the last container's tail jump to the end of command list */
+    if (i == n - 1) {
+      cnt->tail->jump.dst = ctx->command_list.items + ctx->command_list.idx;
+    }
+  }
+}
+
+
+void mu_set_focus(mu_Context *ctx, mu_Id id) {
+  ctx->focus = id;
+  ctx->updated_focus = 1;
+}
+
+
+/* 32bit fnv-1a hash */
+#define HASH_INITIAL 2166136261
+
+static void hash(mu_Id *hash, const void *data, int size) {
+  const unsigned char *p = data;
+  while (size--) {
+    *hash = (*hash ^ *p++) * 16777619;
+  }
+}
+
+
+mu_Id mu_get_id(mu_Context *ctx, const void *data, int size) {
+  int idx = ctx->id_stack.idx;
+  mu_Id res = (idx > 0) ? ctx->id_stack.items[idx - 1] : HASH_INITIAL;
+  hash(&res, data, size);
+  ctx->last_id = res;
+  return res;
+}
+
+
+void mu_push_id(mu_Context *ctx, const void *data, int size) {
+  push(ctx->id_stack, mu_get_id(ctx, data, size));
+}
+
+
+void mu_pop_id(mu_Context *ctx) {
+  pop(ctx->id_stack);
+}
+
+
+void mu_push_clip_rect(mu_Context *ctx, mu_Rect rect) {
+  mu_Rect last = mu_get_clip_rect(ctx);
+  push(ctx->clip_stack, intersect_rects(rect, last));
+}
+
+
+void mu_pop_clip_rect(mu_Context *ctx) {
+  pop(ctx->clip_stack);
+}
+
+
+mu_Rect mu_get_clip_rect(mu_Context *ctx) {
+  expect(ctx->clip_stack.idx > 0);
+  return ctx->clip_stack.items[ctx->clip_stack.idx - 1];
+}
+
+
+int mu_check_clip(mu_Context *ctx, mu_Rect r) {
+  mu_Rect cr = mu_get_clip_rect(ctx);
+  if (r.x > cr.x + cr.w || r.x + r.w < cr.x ||
+      r.y > cr.y + cr.h || r.y + r.h < cr.y   ) { return MU_CLIP_ALL; }
+  if (r.x >= cr.x && r.x + r.w <= cr.x + cr.w &&
+      r.y >= cr.y && r.y + r.h <= cr.y + cr.h ) { return 0; }
+  return MU_CLIP_PART;
+}
+
+
+static void push_layout(mu_Context *ctx, mu_Rect body, mu_Vec2 scroll) {
+  mu_Layout layout;
+  int width = 0;
+  memset(&layout, 0, sizeof(layout));
+  layout.body = mu_rect(body.x - scroll.x, body.y - scroll.y, body.w, body.h);
+  layout.max = mu_vec2(-0x1000000, -0x1000000);
+  push(ctx->layout_stack, layout);
+  mu_layout_row(ctx, 1, &width, 0);
+}
+
+
+static mu_Layout* get_layout(mu_Context *ctx) {
+  return &ctx->layout_stack.items[ctx->layout_stack.idx - 1];
+}
+
+
+static void pop_container(mu_Context *ctx) {
+  mu_Container *cnt = mu_get_current_container(ctx);
+  mu_Layout *layout = get_layout(ctx);
+  cnt->content_size.x = layout->max.x - layout->body.x;
+  cnt->content_size.y = layout->max.y - layout->body.y;
+  /* pop container, layout and id */
+  pop(ctx->container_stack);
+  pop(ctx->layout_stack);
+  mu_pop_id(ctx);
+}
+
+
+mu_Container* mu_get_current_container(mu_Context *ctx) {
+  expect(ctx->container_stack.idx > 0);
+  return ctx->container_stack.items[ ctx->container_stack.idx - 1 ];
+}
+
+
+static mu_Container* get_container(mu_Context *ctx, mu_Id id, int opt) {
+  mu_Container *cnt;
+  /* try to get existing container from pool */
+  int idx = mu_pool_get(ctx, ctx->container_pool, MU_CONTAINERPOOL_SIZE, id);
+  if (idx >= 0) {
+    if (ctx->containers[idx].open || ~opt & MU_OPT_CLOSED) {
+      mu_pool_update(ctx, ctx->container_pool, idx);
+    }
+    return &ctx->containers[idx];
+  }
+  if (opt & MU_OPT_CLOSED) { return NULL; }
+  /* container not found in pool: init new container */
+  idx = mu_pool_init(ctx, ctx->container_pool, MU_CONTAINERPOOL_SIZE, id);
+  cnt = &ctx->containers[idx];
+  memset(cnt, 0, sizeof(*cnt));
+  cnt->open = 1;
+  mu_bring_to_front(ctx, cnt);
+  return cnt;
+}
+
+
+mu_Container* mu_get_container(mu_Context *ctx, const char *name) {
+  mu_Id id = mu_get_id(ctx, name, strlen(name));
+  return get_container(ctx, id, 0);
+}
+
+
+void mu_bring_to_front(mu_Context *ctx, mu_Container *cnt) {
+  cnt->zindex = ++ctx->last_zindex;
+}
+
+
+/*============================================================================
+** pool
+**============================================================================*/
+
+int mu_pool_init(mu_Context *ctx, mu_PoolItem *items, int len, mu_Id id) {
+  int i, n = -1, f = ctx->frame;
+  for (i = 0; i < len; i++) {
+    if (items[i].last_update < f) {
+      f = items[i].last_update;
+      n = i;
+    }
+  }
+  expect(n > -1);
+  items[n].id = id;
+  mu_pool_update(ctx, items, n);
+  return n;
+}
+
+
+int mu_pool_get(mu_Context *ctx, mu_PoolItem *items, int len, mu_Id id) {
+  int i;
+  unused(ctx);
+  for (i = 0; i < len; i++) {
+    if (items[i].id == id) { return i; }
+  }
+  return -1;
+}
+
+
+void mu_pool_update(mu_Context *ctx, mu_PoolItem *items, int idx) {
+  items[idx].last_update = ctx->frame;
+}
+
+
+/*============================================================================
+** input handlers
+**============================================================================*/
+
+void mu_input_mousemove(mu_Context *ctx, int x, int y) {
+  ctx->mouse_pos = mu_vec2(x, y);
+}
+
+
+void mu_input_mousedown(mu_Context *ctx, int x, int y, int btn) {
+  mu_input_mousemove(ctx, x, y);
+  ctx->mouse_down |= btn;
+  ctx->mouse_pressed |= btn;
+}
+
+
+void mu_input_mouseup(mu_Context *ctx, int x, int y, int btn) {
+  mu_input_mousemove(ctx, x, y);
+  ctx->mouse_down &= ~btn;
+}
+
+
+void mu_input_scroll(mu_Context *ctx, int x, int y) {
+  ctx->scroll_delta.x += x;
+  ctx->scroll_delta.y += y;
+}
+
+
+void mu_input_keydown(mu_Context *ctx, int key) {
+  ctx->key_pressed |= key;
+  ctx->key_down |= key;
+}
+
+
+void mu_input_keyup(mu_Context *ctx, int key) {
+  ctx->key_down &= ~key;
+}
+
+
+void mu_input_text(mu_Context *ctx, const char *text) {
+  int len = strlen(ctx->input_text);
+  int size = strlen(text) + 1;
+  expect(len + size <= (int) sizeof(ctx->input_text));
+  memcpy(ctx->input_text + len, text, size);
+}
+
+
+/*============================================================================
+** commandlist
+**============================================================================*/
+
+mu_Command* mu_push_command(mu_Context *ctx, int type, int size) {
+  mu_Command *cmd = (mu_Command*) (ctx->command_list.items + ctx->command_list.idx);
+  expect(ctx->command_list.idx + size < MU_COMMANDLIST_SIZE);
+  cmd->base.type = type;
+  cmd->base.size = size;
+  ctx->command_list.idx += size;
+  return cmd;
+}
+
+
+int mu_next_command(mu_Context *ctx, mu_Command **cmd) {
+  if (*cmd) {
+    *cmd = (mu_Command*) (((char*) *cmd) + (*cmd)->base.size);
+  } else {
+    *cmd = (mu_Command*) ctx->command_list.items;
+  }
+  while ((char*) *cmd != ctx->command_list.items + ctx->command_list.idx) {
+    if ((*cmd)->type != MU_COMMAND_JUMP) { return 1; }
+    *cmd = (*cmd)->jump.dst;
+  }
+  return 0;
+}
+
+
+static mu_Command* push_jump(mu_Context *ctx, mu_Command *dst) {
+  mu_Command *cmd;
+  cmd = mu_push_command(ctx, MU_COMMAND_JUMP, sizeof(mu_JumpCommand));
+  cmd->jump.dst = dst;
+  return cmd;
+}
+
+
+void mu_set_clip(mu_Context *ctx, mu_Rect rect) {
+  mu_Command *cmd;
+  cmd = mu_push_command(ctx, MU_COMMAND_CLIP, sizeof(mu_ClipCommand));
+  cmd->clip.rect = rect;
+}
+
+
+void mu_draw_rect(mu_Context *ctx, mu_Rect rect, mu_Color color) {
+  mu_Command *cmd;
+  rect = intersect_rects(rect, mu_get_clip_rect(ctx));
+  if (rect.w > 0 && rect.h > 0) {
+    cmd = mu_push_command(ctx, MU_COMMAND_RECT, sizeof(mu_RectCommand));
+    cmd->rect.rect = rect;
+    cmd->rect.color = color;
+  }
+}
+
+
+void mu_draw_box(mu_Context *ctx, mu_Rect rect, mu_Color color) {
+  mu_draw_rect(ctx, mu_rect(rect.x + 1, rect.y, rect.w - 2, 1), color);
+  mu_draw_rect(ctx, mu_rect(rect.x + 1, rect.y + rect.h - 1, rect.w - 2, 1), color);
+  mu_draw_rect(ctx, mu_rect(rect.x, rect.y, 1, rect.h), color);
+  mu_draw_rect(ctx, mu_rect(rect.x + rect.w - 1, rect.y, 1, rect.h), color);
+}
+
+
+void mu_draw_text(mu_Context *ctx, mu_Font font, const char *str, int len,
+  mu_Vec2 pos, mu_Color color)
+{
+  mu_Command *cmd;
+  mu_Rect rect = mu_rect(
+    pos.x, pos.y, ctx->text_width(font, str, len), ctx->text_height(font));
+  int clipped = mu_check_clip(ctx, rect);
+  if (clipped == MU_CLIP_ALL ) { return; }
+  if (clipped == MU_CLIP_PART) { mu_set_clip(ctx, mu_get_clip_rect(ctx)); }
+  /* add command */
+  if (len < 0) { len = strlen(str); }
+  cmd = mu_push_command(ctx, MU_COMMAND_TEXT, sizeof(mu_TextCommand) + len);
+  memcpy(cmd->text.str, str, len);
+  cmd->text.str[len] = '\0';
+  cmd->text.pos = pos;
+  cmd->text.color = color;
+  cmd->text.font = font;
+  /* reset clipping if it was set */
+  if (clipped) { mu_set_clip(ctx, unclipped_rect); }
+}
+
+
+void mu_draw_icon(mu_Context *ctx, int id, mu_Rect rect, mu_Color color) {
+  mu_Command *cmd;
+  /* do clip command if the rect isn't fully contained within the cliprect */
+  int clipped = mu_check_clip(ctx, rect);
+  if (clipped == MU_CLIP_ALL ) { return; }
+  if (clipped == MU_CLIP_PART) { mu_set_clip(ctx, mu_get_clip_rect(ctx)); }
+  /* do icon command */
+  cmd = mu_push_command(ctx, MU_COMMAND_ICON, sizeof(mu_IconCommand));
+  cmd->icon.id = id;
+  cmd->icon.rect = rect;
+  cmd->icon.color = color;
+  /* reset clipping if it was set */
+  if (clipped) { mu_set_clip(ctx, unclipped_rect); }
+}
+
+
+/*============================================================================
+** layout
+**============================================================================*/
+
+enum { RELATIVE = 1, ABSOLUTE = 2 };
+
+
+void mu_layout_begin_column(mu_Context *ctx) {
+  push_layout(ctx, mu_layout_next(ctx), mu_vec2(0, 0));
+}
+
+
+void mu_layout_end_column(mu_Context *ctx) {
+  mu_Layout *a, *b;
+  b = get_layout(ctx);
+  pop(ctx->layout_stack);
+  /* inherit position/next_row/max from child layout if they are greater */
+  a = get_layout(ctx);
+  a->position.x = mu_max(a->position.x, b->position.x + b->body.x - a->body.x);
+  a->next_row = mu_max(a->next_row, b->next_row + b->body.y - a->body.y);
+  a->max.x = mu_max(a->max.x, b->max.x);
+  a->max.y = mu_max(a->max.y, b->max.y);
+}
+
+
+void mu_layout_row(mu_Context *ctx, int items, const int *widths, int height) {
+  mu_Layout *layout = get_layout(ctx);
+  if (widths) {
+    expect(items <= MU_MAX_WIDTHS);
+    memcpy(layout->widths, widths, items * sizeof(widths[0]));
+  }
+  layout->items = items;
+  layout->position = mu_vec2(layout->indent, layout->next_row);
+  layout->size.y = height;
+  layout->item_index = 0;
+}
+
+
+void mu_layout_width(mu_Context *ctx, int width) {
+  get_layout(ctx)->size.x = width;
+}
+
+
+void mu_layout_height(mu_Context *ctx, int height) {
+  get_layout(ctx)->size.y = height;
+}
+
+
+void mu_layout_set_next(mu_Context *ctx, mu_Rect r, int relative) {
+  mu_Layout *layout = get_layout(ctx);
+  layout->next = r;
+  layout->next_type = relative ? RELATIVE : ABSOLUTE;
+}
+
+
+mu_Rect mu_layout_next(mu_Context *ctx) {
+  mu_Layout *layout = get_layout(ctx);
+  mu_Style *style = ctx->style;
+  mu_Rect res;
+
+  if (layout->next_type) {
+    /* handle rect set by `mu_layout_set_next` */
+    int type = layout->next_type;
+    layout->next_type = 0;
+    res = layout->next;
+    if (type == ABSOLUTE) { return (ctx->last_rect = res); }
+
+  } else {
+    /* handle next row */
+    if (layout->item_index == layout->items) {
+      mu_layout_row(ctx, layout->items, NULL, layout->size.y);
+    }
+
+    /* position */
+    res.x = layout->position.x;
+    res.y = layout->position.y;
+
+    /* size */
+    res.w = layout->items > 0 ? layout->widths[layout->item_index] : layout->size.x;
+    res.h = layout->size.y;
+    if (res.w == 0) { res.w = style->size.x + style->padding * 2; }
+    if (res.h == 0) { res.h = style->size.y + style->padding * 2; }
+    if (res.w <  0) { res.w += layout->body.w - res.x + 1; }
+    if (res.h <  0) { res.h += layout->body.h - res.y + 1; }
+
+    layout->item_index++;
+  }
+
+  /* update position */
+  layout->position.x += res.w + style->spacing;
+  layout->next_row = mu_max(layout->next_row, res.y + res.h + style->spacing);
+
+  /* apply body offset */
+  res.x += layout->body.x;
+  res.y += layout->body.y;
+
+  /* update max position */
+  layout->max.x = mu_max(layout->max.x, res.x + res.w);
+  layout->max.y = mu_max(layout->max.y, res.y + res.h);
+
+  return (ctx->last_rect = res);
+}
+
+
+/*============================================================================
+** controls
+**============================================================================*/
+
+static int in_hover_root(mu_Context *ctx) {
+  int i = ctx->container_stack.idx;
+  while (i--) {
+    if (ctx->container_stack.items[i] == ctx->hover_root) { return 1; }
+    /* only root containers have their `head` field set; stop searching if we've
+    ** reached the current root container */
+    if (ctx->container_stack.items[i]->head) { break; }
+  }
+  return 0;
+}
+
+
+void mu_draw_control_frame(mu_Context *ctx, mu_Id id, mu_Rect rect,
+  int colorid, int opt)
+{
+  if (opt & MU_OPT_NOFRAME) { return; }
+  colorid += (ctx->focus == id) ? 2 : (ctx->hover == id) ? 1 : 0;
+  ctx->draw_frame(ctx, rect, colorid);
+}
+
+
+void mu_draw_control_text(mu_Context *ctx, const char *str, mu_Rect rect,
+  int colorid, int opt)
+{
+  mu_Vec2 pos;
+  mu_Font font = ctx->style->font;
+  int tw = ctx->text_width(font, str, -1);
+  mu_push_clip_rect(ctx, rect);
+  pos.y = rect.y + (rect.h - ctx->text_height(font)) / 2;
+  if (opt & MU_OPT_ALIGNCENTER) {
+    pos.x = rect.x + (rect.w - tw) / 2;
+  } else if (opt & MU_OPT_ALIGNRIGHT) {
+    pos.x = rect.x + rect.w - tw - ctx->style->padding;
+  } else {
+    pos.x = rect.x + ctx->style->padding;
+  }
+  mu_draw_text(ctx, font, str, -1, pos, ctx->style->colors[colorid]);
+  mu_pop_clip_rect(ctx);
+}
+
+
+int mu_mouse_over(mu_Context *ctx, mu_Rect rect) {
+  return rect_overlaps_vec2(rect, ctx->mouse_pos) &&
+    rect_overlaps_vec2(mu_get_clip_rect(ctx), ctx->mouse_pos) &&
+    in_hover_root(ctx);
+}
+
+
+void mu_update_control(mu_Context *ctx, mu_Id id, mu_Rect rect, int opt) {
+  int mouseover = mu_mouse_over(ctx, rect);
+
+  if (ctx->focus == id) { ctx->updated_focus = 1; }
+  if (opt & MU_OPT_NOINTERACT) { return; }
+  if (mouseover && !ctx->mouse_down) { ctx->hover = id; }
+
+  if (ctx->focus == id) {
+    if (ctx->mouse_pressed && !mouseover) { mu_set_focus(ctx, 0); }
+    if (!ctx->mouse_down && ~opt & MU_OPT_HOLDFOCUS) { mu_set_focus(ctx, 0); }
+  }
+
+  if (ctx->hover == id) {
+    if (ctx->mouse_pressed) {
+      mu_set_focus(ctx, id);
+    } else if (!mouseover) {
+      ctx->hover = 0;
+    }
+  }
+}
+
+
+void mu_text(mu_Context *ctx, const char *text) {
+  const char *start, *end, *p = text;
+  int width = -1;
+  mu_Font font = ctx->style->font;
+  mu_Color color = ctx->style->colors[MU_COLOR_TEXT];
+  mu_layout_begin_column(ctx);
+  mu_layout_row(ctx, 1, &width, ctx->text_height(font));
+  do {
+    mu_Rect r = mu_layout_next(ctx);
+    int w = 0;
+    start = end = p;
+    do {
+      const char* word = p;
+      while (*p && *p != ' ' && *p != '\n') { p++; }
+      w += ctx->text_width(font, word, p - word);
+      if (w > r.w && end != start) { break; }
+      w += ctx->text_width(font, p, 1);
+      end = p++;
+    } while (*end && *end != '\n');
+    mu_draw_text(ctx, font, start, end - start, mu_vec2(r.x, r.y), color);
+    p = end + 1;
+  } while (*end);
+  mu_layout_end_column(ctx);
+}
+
+
+void mu_label(mu_Context *ctx, const char *text) {
+  mu_draw_control_text(ctx, text, mu_layout_next(ctx), MU_COLOR_TEXT, 0);
+}
+
+
+int mu_button_ex(mu_Context *ctx, const char *label, int icon, int opt) {
+  int res = 0;
+  mu_Id id = label ? mu_get_id(ctx, label, strlen(label))
+                   : mu_get_id(ctx, &icon, sizeof(icon));
+  mu_Rect r = mu_layout_next(ctx);
+  mu_update_control(ctx, id, r, opt);
+  /* handle click */
+  if (ctx->mouse_pressed == MU_MOUSE_LEFT && ctx->focus == id) {
+    res |= MU_RES_SUBMIT;
+  }
+  /* draw */
+  mu_draw_control_frame(ctx, id, r, MU_COLOR_BUTTON, opt);
+  if (label) { mu_draw_control_text(ctx, label, r, MU_COLOR_TEXT, opt); }
+  if (icon) { mu_draw_icon(ctx, icon, r, ctx->style->colors[MU_COLOR_TEXT]); }
+  return res;
+}
+
+
+int mu_checkbox(mu_Context *ctx, const char *label, int *state) {
+  int res = 0;
+  mu_Id id = mu_get_id(ctx, &state, sizeof(state));
+  mu_Rect r = mu_layout_next(ctx);
+  mu_Rect box = mu_rect(r.x, r.y, r.h, r.h);
+  mu_update_control(ctx, id, r, 0);
+  /* handle click */
+  if (ctx->mouse_pressed == MU_MOUSE_LEFT && ctx->focus == id) {
+    res |= MU_RES_CHANGE;
+    *state = !*state;
+  }
+  /* draw */
+  mu_draw_control_frame(ctx, id, box, MU_COLOR_BASE, 0);
+  if (*state) {
+    mu_draw_icon(ctx, MU_ICON_CHECK, box, ctx->style->colors[MU_COLOR_TEXT]);
+  }
+  r = mu_rect(r.x + box.w, r.y, r.w - box.w, r.h);
+  mu_draw_control_text(ctx, label, r, MU_COLOR_TEXT, 0);
+  return res;
+}
+
+
+int mu_textbox_raw(mu_Context *ctx, char *buf, int bufsz, mu_Id id, mu_Rect r,
+  int opt)
+{
+  int res = 0;
+  mu_update_control(ctx, id, r, opt | MU_OPT_HOLDFOCUS);
+
+  if (ctx->focus == id) {
+    /* handle text input */
+    int len = strlen(buf);
+    int n = mu_min(bufsz - len - 1, (int) strlen(ctx->input_text));
+    if (n > 0) {
+      memcpy(buf + len, ctx->input_text, n);
+      len += n;
+      buf[len] = '\0';
+      res |= MU_RES_CHANGE;
+    }
+    /* handle backspace */
+    if (ctx->key_pressed & MU_KEY_BACKSPACE && len > 0) {
+      /* skip utf-8 continuation bytes */
+      while ((buf[--len] & 0xc0) == 0x80 && len > 0);
+      buf[len] = '\0';
+      res |= MU_RES_CHANGE;
+    }
+    /* handle return */
+    if (ctx->key_pressed & MU_KEY_RETURN) {
+      mu_set_focus(ctx, 0);
+      res |= MU_RES_SUBMIT;
+    }
+  }
+
+  /* draw */
+  mu_draw_control_frame(ctx, id, r, MU_COLOR_BASE, opt);
+  if (ctx->focus == id) {
+    mu_Color color = ctx->style->colors[MU_COLOR_TEXT];
+    mu_Font font = ctx->style->font;
+    int textw = ctx->text_width(font, buf, -1);
+    int texth = ctx->text_height(font);
+    int ofx = r.w - ctx->style->padding - textw - 1;
+    int textx = r.x + mu_min(ofx, ctx->style->padding);
+    int texty = r.y + (r.h - texth) / 2;
+    mu_push_clip_rect(ctx, r);
+    mu_draw_text(ctx, font, buf, -1, mu_vec2(textx, texty), color);
+    mu_draw_rect(ctx, mu_rect(textx + textw, texty, 1, texth), color);
+    mu_pop_clip_rect(ctx);
+  } else {
+    mu_draw_control_text(ctx, buf, r, MU_COLOR_TEXT, opt);
+  }
+
+  return res;
+}
+
+
+static int number_textbox(mu_Context *ctx, mu_Real *value, mu_Rect r, mu_Id id) {
+  if (ctx->mouse_pressed == MU_MOUSE_LEFT && ctx->key_down & MU_KEY_SHIFT &&
+      ctx->hover == id
+  ) {
+    ctx->number_edit = id;
+    sprintf(ctx->number_edit_buf, MU_REAL_FMT, *value);
+  }
+  if (ctx->number_edit == id) {
+    int res = mu_textbox_raw(
+      ctx, ctx->number_edit_buf, sizeof(ctx->number_edit_buf), id, r, 0);
+    if (res & MU_RES_SUBMIT || ctx->focus != id) {
+      *value = strtod(ctx->number_edit_buf, NULL);
+      ctx->number_edit = 0;
+    } else {
+      return 1;
+    }
+  }
+  return 0;
+}
+
+
+int mu_textbox_ex(mu_Context *ctx, char *buf, int bufsz, int opt) {
+  mu_Id id = mu_get_id(ctx, &buf, sizeof(buf));
+  mu_Rect r = mu_layout_next(ctx);
+  return mu_textbox_raw(ctx, buf, bufsz, id, r, opt);
+}
+
+
+int mu_slider_ex(mu_Context *ctx, mu_Real *value, mu_Real low, mu_Real high,
+  mu_Real step, const char *fmt, int opt)
+{
+  char buf[MU_MAX_FMT + 1];
+  mu_Rect thumb;
+  int x, w, res = 0;
+  mu_Real last = *value, v = last;
+  mu_Id id = mu_get_id(ctx, &value, sizeof(value));
+  mu_Rect base = mu_layout_next(ctx);
+
+  /* handle text input mode */
+  if (number_textbox(ctx, &v, base, id)) { return res; }
+
+  /* handle normal mode */
+  mu_update_control(ctx, id, base, opt);
+
+  /* handle input */
+  if (ctx->focus == id &&
+      (ctx->mouse_down | ctx->mouse_pressed) == MU_MOUSE_LEFT)
+  {
+    v = low + (ctx->mouse_pos.x - base.x) * (high - low) / base.w;
+    if (step) { v = (((v + step / 2) / step)) * step; }
+  }
+  /* clamp and store value, update res */
+  *value = v = mu_clamp(v, low, high);
+  if (last != v) { res |= MU_RES_CHANGE; }
+
+  /* draw base */
+  mu_draw_control_frame(ctx, id, base, MU_COLOR_BASE, opt);
+  /* draw thumb */
+  w = ctx->style->thumb_size;
+  x = (v - low) * (base.w - w) / (high - low);
+  thumb = mu_rect(base.x + x, base.y, w, base.h);
+  mu_draw_control_frame(ctx, id, thumb, MU_COLOR_BUTTON, opt);
+  /* draw text  */
+  sprintf(buf, fmt, v);
+  mu_draw_control_text(ctx, buf, base, MU_COLOR_TEXT, opt);
+
+  return res;
+}
+
+
+int mu_number_ex(mu_Context *ctx, mu_Real *value, mu_Real step,
+  const char *fmt, int opt)
+{
+  char buf[MU_MAX_FMT + 1];
+  int res = 0;
+  mu_Id id = mu_get_id(ctx, &value, sizeof(value));
+  mu_Rect base = mu_layout_next(ctx);
+  mu_Real last = *value;
+
+  /* handle text input mode */
+  if (number_textbox(ctx, value, base, id)) { return res; }
+
+  /* handle normal mode */
+  mu_update_control(ctx, id, base, opt);
+
+  /* handle input */
+  if (ctx->focus == id && ctx->mouse_down == MU_MOUSE_LEFT) {
+    *value += ctx->mouse_delta.x * step;
+  }
+  /* set flag if value changed */
+  if (*value != last) { res |= MU_RES_CHANGE; }
+
+  /* draw base */
+  mu_draw_control_frame(ctx, id, base, MU_COLOR_BASE, opt);
+  /* draw text  */
+  sprintf(buf, fmt, *value);
+  mu_draw_control_text(ctx, buf, base, MU_COLOR_TEXT, opt);
+
+  return res;
+}
+
+
+static int header(mu_Context *ctx, const char *label, int istreenode, int opt) {
+  mu_Rect r;
+  int active, expanded;
+  mu_Id id = mu_get_id(ctx, label, strlen(label));
+  int idx = mu_pool_get(ctx, ctx->treenode_pool, MU_TREENODEPOOL_SIZE, id);
+  int width = -1;
+  mu_layout_row(ctx, 1, &width, 0);
+
+  active = (idx >= 0);
+  expanded = (opt & MU_OPT_EXPANDED) ? !active : active;
+  r = mu_layout_next(ctx);
+  mu_update_control(ctx, id, r, 0);
+
+  /* handle click */
+  active ^= (ctx->mouse_pressed == MU_MOUSE_LEFT && ctx->focus == id);
+
+  /* update pool ref */
+  if (idx >= 0) {
+    if (active) { mu_pool_update(ctx, ctx->treenode_pool, idx); }
+           else { memset(&ctx->treenode_pool[idx], 0, sizeof(mu_PoolItem)); }
+  } else if (active) {
+    mu_pool_init(ctx, ctx->treenode_pool, MU_TREENODEPOOL_SIZE, id);
+  }
+
+  /* draw */
+  if (istreenode) {
+    if (ctx->hover == id) { ctx->draw_frame(ctx, r, MU_COLOR_BUTTONHOVER); }
+  } else {
+    mu_draw_control_frame(ctx, id, r, MU_COLOR_BUTTON, 0);
+  }
+  mu_draw_icon(
+    ctx, expanded ? MU_ICON_EXPANDED : MU_ICON_COLLAPSED,
+    mu_rect(r.x, r.y, r.h, r.h), ctx->style->colors[MU_COLOR_TEXT]);
+  r.x += r.h - ctx->style->padding;
+  r.w -= r.h - ctx->style->padding;
+  mu_draw_control_text(ctx, label, r, MU_COLOR_TEXT, 0);
+
+  return expanded ? MU_RES_ACTIVE : 0;
+}
+
+
+int mu_header_ex(mu_Context *ctx, const char *label, int opt) {
+  return header(ctx, label, 0, opt);
+}
+
+
+int mu_begin_treenode_ex(mu_Context *ctx, const char *label, int opt) {
+  int res = header(ctx, label, 1, opt);
+  if (res & MU_RES_ACTIVE) {
+    get_layout(ctx)->indent += ctx->style->indent;
+    push(ctx->id_stack, ctx->last_id);
+  }
+  return res;
+}
+
+
+void mu_end_treenode(mu_Context *ctx) {
+  get_layout(ctx)->indent -= ctx->style->indent;
+  mu_pop_id(ctx);
+}
+
+
+#define scrollbar(ctx, cnt, b, cs, x, y, w, h)                              \
+  do {                                                                      \
+    /* only add scrollbar if content size is larger than body */            \
+    int maxscroll = cs.y - b->h;                                            \
+                                                                            \
+    if (maxscroll > 0 && b->h > 0) {                                        \
+      mu_Rect base, thumb;                                                  \
+      mu_Id id = mu_get_id(ctx, "!scrollbar" #y, 11);                       \
+                                                                            \
+      /* get sizing / positioning */                                        \
+      base = *b;                                                            \
+      base.x = b->x + b->w;                                                 \
+      base.w = ctx->style->scrollbar_size;                                  \
+                                                                            \
+      /* handle input */                                                    \
+      mu_update_control(ctx, id, base, 0);                                  \
+      if (ctx->focus == id && ctx->mouse_down == MU_MOUSE_LEFT) {           \
+        cnt->scroll.y += ctx->mouse_delta.y * cs.y / base.h;                \
+      }                                                                     \
+      /* clamp scroll to limits */                                          \
+      cnt->scroll.y = mu_clamp(cnt->scroll.y, 0, maxscroll);                \
+                                                                            \
+      /* draw base and thumb */                                             \
+      ctx->draw_frame(ctx, base, MU_COLOR_SCROLLBASE);                      \
+      thumb = base;                                                         \
+      thumb.h = mu_max(ctx->style->thumb_size, base.h * b->h / cs.y);       \
+      thumb.y += cnt->scroll.y * (base.h - thumb.h) / maxscroll;            \
+      ctx->draw_frame(ctx, thumb, MU_COLOR_SCROLLTHUMB);                    \
+                                                                            \
+      /* set this as the scroll_target (will get scrolled on mousewheel) */ \
+      /* if the mouse is over it */                                         \
+      if (mu_mouse_over(ctx, *b)) { ctx->scroll_target = cnt; }             \
+    } else {                                                                \
+      cnt->scroll.y = 0;                                                    \
+    }                                                                       \
+  } while (0)
+
+
+static void scrollbars(mu_Context *ctx, mu_Container *cnt, mu_Rect *body) {
+  int sz = ctx->style->scrollbar_size;
+  mu_Vec2 cs = cnt->content_size;
+  cs.x += ctx->style->padding * 2;
+  cs.y += ctx->style->padding * 2;
+  mu_push_clip_rect(ctx, *body);
+  /* resize body to make room for scrollbars */
+  if (cs.y > cnt->body.h) { body->w -= sz; }
+  if (cs.x > cnt->body.w) { body->h -= sz; }
+  /* to create a horizontal or vertical scrollbar almost-identical code is
+  ** used; only the references to `x|y` `w|h` need to be switched */
+  scrollbar(ctx, cnt, body, cs, x, y, w, h);
+  scrollbar(ctx, cnt, body, cs, y, x, h, w);
+  mu_pop_clip_rect(ctx);
+}
+
+
+static void push_container_body(
+  mu_Context *ctx, mu_Container *cnt, mu_Rect body, int opt
+) {
+  if (~opt & MU_OPT_NOSCROLL) { scrollbars(ctx, cnt, &body); }
+  push_layout(ctx, expand_rect(body, -ctx->style->padding), cnt->scroll);
+  cnt->body = body;
+}
+
+
+static void begin_root_container(mu_Context *ctx, mu_Container *cnt) {
+  push(ctx->container_stack, cnt);
+  /* push container to roots list and push head command */
+  push(ctx->root_list, cnt);
+  cnt->head = push_jump(ctx, NULL);
+  /* set as hover root if the mouse is overlapping this container and it has a
+  ** higher zindex than the current hover root */
+  if (rect_overlaps_vec2(cnt->rect, ctx->mouse_pos) &&
+      (!ctx->next_hover_root || cnt->zindex > ctx->next_hover_root->zindex)
+  ) {
+    ctx->next_hover_root = cnt;
+  }
+  /* clipping is reset here in case a root-container is made within
+  ** another root-containers's begin/end block; this prevents the inner
+  ** root-container being clipped to the outer */
+  push(ctx->clip_stack, unclipped_rect);
+}
+
+
+static void end_root_container(mu_Context *ctx) {
+  /* push tail 'goto' jump command and set head 'skip' command. the final steps
+  ** on initing these are done in mu_end() */
+  mu_Container *cnt = mu_get_current_container(ctx);
+  cnt->tail = push_jump(ctx, NULL);
+  cnt->head->jump.dst = ctx->command_list.items + ctx->command_list.idx;
+  /* pop base clip rect and container */
+  mu_pop_clip_rect(ctx);
+  pop_container(ctx);
+}
+
+
+int mu_begin_window_ex(mu_Context *ctx, const char *title, mu_Rect rect, int opt) {
+  mu_Rect body;
+  mu_Id id = mu_get_id(ctx, title, strlen(title));
+  mu_Container *cnt = get_container(ctx, id, opt);
+  if (!cnt || !cnt->open) { return 0; }
+  push(ctx->id_stack, id);
+
+  if (cnt->rect.w == 0) { cnt->rect = rect; }
+  begin_root_container(ctx, cnt);
+  rect = body = cnt->rect;
+
+  /* draw frame */
+  if (~opt & MU_OPT_NOFRAME) {
+    ctx->draw_frame(ctx, rect, MU_COLOR_WINDOWBG);
+  }
+
+  /* do title bar */
+  if (~opt & MU_OPT_NOTITLE) {
+    mu_Rect tr = rect;
+    tr.h = ctx->style->title_height;
+    ctx->draw_frame(ctx, tr, MU_COLOR_TITLEBG);
+
+    /* do title text */
+    if (~opt & MU_OPT_NOTITLE) {
+      mu_Id id = mu_get_id(ctx, "!title", 6);
+      mu_update_control(ctx, id, tr, opt);
+      mu_draw_control_text(ctx, title, tr, MU_COLOR_TITLETEXT, opt);
+      if (id == ctx->focus && ctx->mouse_down == MU_MOUSE_LEFT) {
+        cnt->rect.x += ctx->mouse_delta.x;
+        cnt->rect.y += ctx->mouse_delta.y;
+      }
+      body.y += tr.h;
+      body.h -= tr.h;
+    }
+
+    /* do `close` button */
+    if (~opt & MU_OPT_NOCLOSE) {
+      mu_Id id = mu_get_id(ctx, "!close", 6);
+      mu_Rect r = mu_rect(tr.x + tr.w - tr.h, tr.y, tr.h, tr.h);
+      tr.w -= r.w;
+      mu_draw_icon(ctx, MU_ICON_CLOSE, r, ctx->style->colors[MU_COLOR_TITLETEXT]);
+      mu_update_control(ctx, id, r, opt);
+      if (ctx->mouse_pressed == MU_MOUSE_LEFT && id == ctx->focus) {
+        cnt->open = 0;
+      }
+    }
+  }
+
+  push_container_body(ctx, cnt, body, opt);
+
+  /* do `resize` handle */
+  if (~opt & MU_OPT_NORESIZE) {
+    int sz = ctx->style->title_height;
+    mu_Id id = mu_get_id(ctx, "!resize", 7);
+    mu_Rect r = mu_rect(rect.x + rect.w - sz, rect.y + rect.h - sz, sz, sz);
+    mu_update_control(ctx, id, r, opt);
+    if (id == ctx->focus && ctx->mouse_down == MU_MOUSE_LEFT) {
+      cnt->rect.w = mu_max(96, cnt->rect.w + ctx->mouse_delta.x);
+      cnt->rect.h = mu_max(64, cnt->rect.h + ctx->mouse_delta.y);
+    }
+  }
+
+  /* resize to content size */
+  if (opt & MU_OPT_AUTOSIZE) {
+    mu_Rect r = get_layout(ctx)->body;
+    cnt->rect.w = cnt->content_size.x + (cnt->rect.w - r.w);
+    cnt->rect.h = cnt->content_size.y + (cnt->rect.h - r.h);
+  }
+
+  /* close if this is a popup window and elsewhere was clicked */
+  if (opt & MU_OPT_POPUP && ctx->mouse_pressed && ctx->hover_root != cnt) {
+    cnt->open = 0;
+  }
+
+  mu_push_clip_rect(ctx, cnt->body);
+  return MU_RES_ACTIVE;
+}
+
+
+void mu_end_window(mu_Context *ctx) {
+  mu_pop_clip_rect(ctx);
+  end_root_container(ctx);
+}
+
+
+void mu_open_popup(mu_Context *ctx, const char *name) {
+  mu_Container *cnt = mu_get_container(ctx, name);
+  /* set as hover root so popup isn't closed in begin_window_ex()  */
+  ctx->hover_root = ctx->next_hover_root = cnt;
+  /* position at mouse cursor, open and bring-to-front */
+  cnt->rect = mu_rect(ctx->mouse_pos.x, ctx->mouse_pos.y, 1, 1);
+  cnt->open = 1;
+  mu_bring_to_front(ctx, cnt);
+}
+
+
+int mu_begin_popup(mu_Context *ctx, const char *name) {
+  int opt = MU_OPT_POPUP | MU_OPT_AUTOSIZE | MU_OPT_NORESIZE |
+            MU_OPT_NOSCROLL | MU_OPT_NOTITLE | MU_OPT_CLOSED;
+  return mu_begin_window_ex(ctx, name, mu_rect(0, 0, 0, 0), opt);
+}
+
+
+void mu_end_popup(mu_Context *ctx) {
+  mu_end_window(ctx);
+}
+
+
+void mu_begin_panel_ex(mu_Context *ctx, const char *name, int opt) {
+  mu_Container *cnt;
+  mu_push_id(ctx, name, strlen(name));
+  cnt = get_container(ctx, ctx->last_id, opt);
+  cnt->rect = mu_layout_next(ctx);
+  if (~opt & MU_OPT_NOFRAME) {
+    ctx->draw_frame(ctx, cnt->rect, MU_COLOR_PANELBG);
+  }
+  push(ctx->container_stack, cnt);
+  push_container_body(ctx, cnt, cnt->rect, opt);
+  mu_push_clip_rect(ctx, cnt->body);
+}
+
+
+void mu_end_panel(mu_Context *ctx) {
+  mu_pop_clip_rect(ctx);
+  pop_container(ctx);
+}
diff --git a/src/lib/microui.h b/src/lib/microui.h
new file mode 100644
index 0000000..78a1a34
--- /dev/null
+++ b/src/lib/microui.h
@@ -0,0 +1,296 @@
+/*
+** Copyright (c) 2020 rxi
+**
+** This library is free software; you can redistribute it and/or modify it
+** under the terms of the MIT license. See `microui.c` for details.
+*/
+
+#ifndef MICROUI_H
+#define MICROUI_H
+
+#define MU_VERSION "2.01"
+
+#define MU_COMMANDLIST_SIZE     (256 * 1024)
+#define MU_ROOTLIST_SIZE        32
+#define MU_CONTAINERSTACK_SIZE  32
+#define MU_CLIPSTACK_SIZE       32
+#define MU_IDSTACK_SIZE         32
+#define MU_LAYOUTSTACK_SIZE     16
+#define MU_CONTAINERPOOL_SIZE   48
+#define MU_TREENODEPOOL_SIZE    48
+#define MU_MAX_WIDTHS           16
+#define MU_REAL                 float
+#define MU_REAL_FMT             "%.3g"
+#define MU_SLIDER_FMT           "%.2f"
+#define MU_MAX_FMT              127
+
+#define mu_stack(T, n)          struct { int idx; T items[n]; }
+#define mu_min(a, b)            ((a) < (b) ? (a) : (b))
+#define mu_max(a, b)            ((a) > (b) ? (a) : (b))
+#define mu_clamp(x, a, b)       mu_min(b, mu_max(a, x))
+
+enum {
+  MU_CLIP_PART = 1,
+  MU_CLIP_ALL
+};
+
+enum {
+  MU_COMMAND_JUMP = 1,
+  MU_COMMAND_CLIP,
+  MU_COMMAND_RECT,
+  MU_COMMAND_TEXT,
+  MU_COMMAND_ICON,
+  MU_COMMAND_MAX
+};
+
+enum {
+  MU_COLOR_TEXT,
+  MU_COLOR_BORDER,
+  MU_COLOR_WINDOWBG,
+  MU_COLOR_TITLEBG,
+  MU_COLOR_TITLETEXT,
+  MU_COLOR_PANELBG,
+  MU_COLOR_BUTTON,
+  MU_COLOR_BUTTONHOVER,
+  MU_COLOR_BUTTONFOCUS,
+  MU_COLOR_BASE,
+  MU_COLOR_BASEHOVER,
+  MU_COLOR_BASEFOCUS,
+  MU_COLOR_SCROLLBASE,
+  MU_COLOR_SCROLLTHUMB,
+  MU_COLOR_MAX
+};
+
+enum {
+  MU_ICON_CLOSE = 1,
+  MU_ICON_CHECK,
+  MU_ICON_COLLAPSED,
+  MU_ICON_EXPANDED,
+  MU_ICON_MAX
+};
+
+enum {
+  MU_RES_ACTIVE       = (1 << 0),
+  MU_RES_SUBMIT       = (1 << 1),
+  MU_RES_CHANGE       = (1 << 2)
+};
+
+enum {
+  MU_OPT_ALIGNCENTER  = (1 << 0),
+  MU_OPT_ALIGNRIGHT   = (1 << 1),
+  MU_OPT_NOINTERACT   = (1 << 2),
+  MU_OPT_NOFRAME      = (1 << 3),
+  MU_OPT_NORESIZE     = (1 << 4),
+  MU_OPT_NOSCROLL     = (1 << 5),
+  MU_OPT_NOCLOSE      = (1 << 6),
+  MU_OPT_NOTITLE      = (1 << 7),
+  MU_OPT_HOLDFOCUS    = (1 << 8),
+  MU_OPT_AUTOSIZE     = (1 << 9),
+  MU_OPT_POPUP        = (1 << 10),
+  MU_OPT_CLOSED       = (1 << 11),
+  MU_OPT_EXPANDED     = (1 << 12)
+};
+
+enum {
+  MU_MOUSE_LEFT       = (1 << 0),
+  MU_MOUSE_RIGHT      = (1 << 1),
+  MU_MOUSE_MIDDLE     = (1 << 2)
+};
+
+enum {
+  MU_KEY_SHIFT        = (1 << 0),
+  MU_KEY_CTRL         = (1 << 1),
+  MU_KEY_ALT          = (1 << 2),
+  MU_KEY_BACKSPACE    = (1 << 3),
+  MU_KEY_RETURN       = (1 << 4)
+};
+
+
+typedef struct mu_Context mu_Context;
+typedef unsigned mu_Id;
+typedef MU_REAL mu_Real;
+typedef void* mu_Font;
+
+typedef struct { int x, y; } mu_Vec2;
+typedef struct { int x, y, w, h; } mu_Rect;
+typedef struct { unsigned char r, g, b, a; } mu_Color;
+typedef struct { mu_Id id; int last_update; } mu_PoolItem;
+
+typedef struct { int type, size; } mu_BaseCommand;
+typedef struct { mu_BaseCommand base; void *dst; } mu_JumpCommand;
+typedef struct { mu_BaseCommand base; mu_Rect rect; } mu_ClipCommand;
+typedef struct { mu_BaseCommand base; mu_Rect rect; mu_Color color; } mu_RectCommand;
+typedef struct { mu_BaseCommand base; mu_Font font; mu_Vec2 pos; mu_Color color; char str[1]; } mu_TextCommand;
+typedef struct { mu_BaseCommand base; mu_Rect rect; int id; mu_Color color; } mu_IconCommand;
+
+typedef union {
+  int type;
+  mu_BaseCommand base;
+  mu_JumpCommand jump;
+  mu_ClipCommand clip;
+  mu_RectCommand rect;
+  mu_TextCommand text;
+  mu_IconCommand icon;
+} mu_Command;
+
+typedef struct {
+  mu_Rect body;
+  mu_Rect next;
+  mu_Vec2 position;
+  mu_Vec2 size;
+  mu_Vec2 max;
+  int widths[MU_MAX_WIDTHS];
+  int items;
+  int item_index;
+  int next_row;
+  int next_type;
+  int indent;
+} mu_Layout;
+
+typedef struct {
+  mu_Command *head, *tail;
+  mu_Rect rect;
+  mu_Rect body;
+  mu_Vec2 content_size;
+  mu_Vec2 scroll;
+  int zindex;
+  int open;
+} mu_Container;
+
+typedef struct {
+  mu_Font font;
+  mu_Vec2 size;
+  int padding;
+  int spacing;
+  int indent;
+  int title_height;
+  int scrollbar_size;
+  int thumb_size;
+  mu_Color colors[MU_COLOR_MAX];
+} mu_Style;
+
+struct mu_Context {
+  /* callbacks */
+  int (*text_width)(mu_Font font, const char *str, int len);
+  int (*text_height)(mu_Font font);
+  void (*draw_frame)(mu_Context *ctx, mu_Rect rect, int colorid);
+  /* core state */
+  mu_Style _style;
+  mu_Style *style;
+  mu_Id hover;
+  mu_Id focus;
+  mu_Id last_id;
+  mu_Rect last_rect;
+  int last_zindex;
+  int updated_focus;
+  int frame;
+  mu_Container *hover_root;
+  mu_Container *next_hover_root;
+  mu_Container *scroll_target;
+  char number_edit_buf[MU_MAX_FMT];
+  mu_Id number_edit;
+  /* stacks */
+  mu_stack(char, MU_COMMANDLIST_SIZE) command_list;
+  mu_stack(mu_Container*, MU_ROOTLIST_SIZE) root_list;
+  mu_stack(mu_Container*, MU_CONTAINERSTACK_SIZE) container_stack;
+  mu_stack(mu_Rect, MU_CLIPSTACK_SIZE) clip_stack;
+  mu_stack(mu_Id, MU_IDSTACK_SIZE) id_stack;
+  mu_stack(mu_Layout, MU_LAYOUTSTACK_SIZE) layout_stack;
+  /* retained state pools */
+  mu_PoolItem container_pool[MU_CONTAINERPOOL_SIZE];
+  mu_Container containers[MU_CONTAINERPOOL_SIZE];
+  mu_PoolItem treenode_pool[MU_TREENODEPOOL_SIZE];
+  /* input state */
+  mu_Vec2 mouse_pos;
+  mu_Vec2 last_mouse_pos;
+  mu_Vec2 mouse_delta;
+  mu_Vec2 scroll_delta;
+  int mouse_down;
+  int mouse_pressed;
+  int key_down;
+  int key_pressed;
+  char input_text[32];
+};
+
+
+mu_Vec2 mu_vec2(int x, int y);
+mu_Rect mu_rect(int x, int y, int w, int h);
+mu_Color mu_color(int r, int g, int b, int a);
+
+void mu_init(mu_Context *ctx);
+void mu_begin(mu_Context *ctx);
+void mu_end(mu_Context *ctx);
+void mu_set_focus(mu_Context *ctx, mu_Id id);
+mu_Id mu_get_id(mu_Context *ctx, const void *data, int size);
+void mu_push_id(mu_Context *ctx, const void *data, int size);
+void mu_pop_id(mu_Context *ctx);
+void mu_push_clip_rect(mu_Context *ctx, mu_Rect rect);
+void mu_pop_clip_rect(mu_Context *ctx);
+mu_Rect mu_get_clip_rect(mu_Context *ctx);
+int mu_check_clip(mu_Context *ctx, mu_Rect r);
+mu_Container* mu_get_current_container(mu_Context *ctx);
+mu_Container* mu_get_container(mu_Context *ctx, const char *name);
+void mu_bring_to_front(mu_Context *ctx, mu_Container *cnt);
+
+int mu_pool_init(mu_Context *ctx, mu_PoolItem *items, int len, mu_Id id);
+int mu_pool_get(mu_Context *ctx, mu_PoolItem *items, int len, mu_Id id);
+void mu_pool_update(mu_Context *ctx, mu_PoolItem *items, int idx);
+
+void mu_input_mousemove(mu_Context *ctx, int x, int y);
+void mu_input_mousedown(mu_Context *ctx, int x, int y, int btn);
+void mu_input_mouseup(mu_Context *ctx, int x, int y, int btn);
+void mu_input_scroll(mu_Context *ctx, int x, int y);
+void mu_input_keydown(mu_Context *ctx, int key);
+void mu_input_keyup(mu_Context *ctx, int key);
+void mu_input_text(mu_Context *ctx, const char *text);
+
+mu_Command* mu_push_command(mu_Context *ctx, int type, int size);
+int mu_next_command(mu_Context *ctx, mu_Command **cmd);
+void mu_set_clip(mu_Context *ctx, mu_Rect rect);
+void mu_draw_rect(mu_Context *ctx, mu_Rect rect, mu_Color color);
+void mu_draw_box(mu_Context *ctx, mu_Rect rect, mu_Color color);
+void mu_draw_text(mu_Context *ctx, mu_Font font, const char *str, int len, mu_Vec2 pos, mu_Color color);
+void mu_draw_icon(mu_Context *ctx, int id, mu_Rect rect, mu_Color color);
+
+void mu_layout_row(mu_Context *ctx, int items, const int *widths, int height);
+void mu_layout_width(mu_Context *ctx, int width);
+void mu_layout_height(mu_Context *ctx, int height);
+void mu_layout_begin_column(mu_Context *ctx);
+void mu_layout_end_column(mu_Context *ctx);
+void mu_layout_set_next(mu_Context *ctx, mu_Rect r, int relative);
+mu_Rect mu_layout_next(mu_Context *ctx);
+
+void mu_draw_control_frame(mu_Context *ctx, mu_Id id, mu_Rect rect, int colorid, int opt);
+void mu_draw_control_text(mu_Context *ctx, const char *str, mu_Rect rect, int colorid, int opt);
+int mu_mouse_over(mu_Context *ctx, mu_Rect rect);
+void mu_update_control(mu_Context *ctx, mu_Id id, mu_Rect rect, int opt);
+
+#define mu_button(ctx, label)             mu_button_ex(ctx, label, 0, MU_OPT_ALIGNCENTER)
+#define mu_textbox(ctx, buf, bufsz)       mu_textbox_ex(ctx, buf, bufsz, 0)
+#define mu_slider(ctx, value, lo, hi)     mu_slider_ex(ctx, value, lo, hi, 0, MU_SLIDER_FMT, MU_OPT_ALIGNCENTER)
+#define mu_number(ctx, value, step)       mu_number_ex(ctx, value, step, MU_SLIDER_FMT, MU_OPT_ALIGNCENTER)
+#define mu_header(ctx, label)             mu_header_ex(ctx, label, 0)
+#define mu_begin_treenode(ctx, label)     mu_begin_treenode_ex(ctx, label, 0)
+#define mu_begin_window(ctx, title, rect) mu_begin_window_ex(ctx, title, rect, 0)
+#define mu_begin_panel(ctx, name)         mu_begin_panel_ex(ctx, name, 0)
+
+void mu_text(mu_Context *ctx, const char *text);
+void mu_label(mu_Context *ctx, const char *text);
+int mu_button_ex(mu_Context *ctx, const char *label, int icon, int opt);
+int mu_checkbox(mu_Context *ctx, const char *label, int *state);
+int mu_textbox_raw(mu_Context *ctx, char *buf, int bufsz, mu_Id id, mu_Rect r, int opt);
+int mu_textbox_ex(mu_Context *ctx, char *buf, int bufsz, int opt);
+int mu_slider_ex(mu_Context *ctx, mu_Real *value, mu_Real low, mu_Real high, mu_Real step, const char *fmt, int opt);
+int mu_number_ex(mu_Context *ctx, mu_Real *value, mu_Real step, const char *fmt, int opt);
+int mu_header_ex(mu_Context *ctx, const char *label, int opt);
+int mu_begin_treenode_ex(mu_Context *ctx, const char *label, int opt);
+void mu_end_treenode(mu_Context *ctx);
+int mu_begin_window_ex(mu_Context *ctx, const char *title, mu_Rect rect, int opt);
+void mu_end_window(mu_Context *ctx);
+void mu_open_popup(mu_Context *ctx, const char *name);
+int mu_begin_popup(mu_Context *ctx, const char *name);
+void mu_end_popup(mu_Context *ctx);
+void mu_begin_panel_ex(mu_Context *ctx, const char *name, int opt);
+void mu_end_panel(mu_Context *ctx);
+
+#endif
diff --git a/src/raylua_builder_ui.c b/src/raylua_builder_ui.c
new file mode 100644
index 0000000..6292194
--- /dev/null
+++ b/src/raylua_builder_ui.c
@@ -0,0 +1,131 @@
+/*
+  Copyright (C) 2020 Astie Teddy
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+  OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+  CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <stdio.h>
+
+#include <raylib.h>
+#include "lib/microui.c"
+#include "lib/microui.h"
+
+#ifdef WIN32
+#include "lib/dirent.h"
+#define stat _stat
+#else
+#include <dirent.h>
+#endif
+
+#ifdef WIN32
+//#include <windows.h>
+#endif
+
+#undef DrawText
+
+static int get_text_width(mu_Font font, const char *str, int len)
+{
+  if (font == NULL)
+    return MeasureText(str, 10);
+}
+
+static int get_text_height(mu_Font font)
+{
+  return 10;
+}
+
+void builder_menu(mu_Context *ctx)
+{
+  if (mu_begin_window(ctx, "raylua builder", mu_rect(0, 0, 400, 290))) {
+
+    mu_layout_row(ctx, 1, (int []){ -1 }, -1);
+
+    DIR *dir = opendir(".");
+    struct dirent *ent = NULL;
+
+    while ((ent = readdir(dir)))
+      mu_text(ctx, ent->d_name);
+
+    closedir(dir);
+
+    mu_end_window(ctx);
+  }
+}
+
+int raylua_builder_boot_ui(FILE *self)
+{
+  #ifdef WIN32
+  //FreeConsole();
+  #endif
+
+  //SetTraceLogLevel(LOG_WARNING);
+  SetConfigFlags(FLAG_VSYNC_HINT);
+  InitWindow(400, 300, "raylua builder ui");
+  
+  mu_Context *ctx = malloc(sizeof(mu_Context));
+  mu_init(ctx);
+
+  ctx->text_width = get_text_width;
+  ctx->text_height = get_text_height;
+
+  while (!WindowShouldClose()) {
+
+    int mx = GetMouseX(), my = GetMouseY();
+
+    if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
+      mu_input_mousedown(ctx, mx, my, MU_MOUSE_LEFT);
+    if (IsMouseButtonUp(MOUSE_LEFT_BUTTON))
+      mu_input_mouseup(ctx, mx, my, MU_MOUSE_LEFT);
+
+    mu_input_mousemove(&ctx, mx, my);
+
+    mu_begin(ctx);
+    builder_menu(ctx);
+    mu_end(ctx);
+
+    BeginDrawing();
+    ClearBackground(RAYWHITE);
+
+    mu_Command *cmd = NULL;
+    while (mu_next_command(ctx, &cmd)) {
+      if (cmd->type == MU_COMMAND_TEXT) {
+        Color c = {
+          .r = cmd->text.color.r,
+          .g = cmd->text.color.g,
+          .b = cmd->text.color.b,
+          .a = cmd->text.color.a
+        };
+
+        DrawText(cmd->text.str, cmd->text.pos.x, cmd->text.pos.y, 10, c);
+      }
+      if (cmd->type == MU_COMMAND_RECT) {
+        Color c = {
+          .r = cmd->rect.color.r,
+          .g = cmd->rect.color.g,
+          .b = cmd->rect.color.b,
+          .a = cmd->rect.color.a
+        };
+        mu_Rect rect = cmd->rect.rect;
+
+        DrawRectangle(rect.x, rect.y, rect.w, rect.h, c);
+      }
+      if (cmd->type == MU_COMMAND_CLIP) {
+        BeginScissorMode(cmd->clip.rect.x, cmd->clip.rect.y, cmd->clip.rect.w, cmd->clip.rect.h);
+      }
+    }
+
+    EndScissorMode();
+
+    EndDrawing();
+  }
+}
\ No newline at end of file
diff --git a/src/raylua_e.c b/src/raylua_e.c
index 5dad6ba..9104358 100644
--- a/src/raylua_e.c
+++ b/src/raylua_e.c
@@ -32,6 +32,7 @@ FILE *raylua_open_self(const char *argv0);
 
 #ifndef RAYLUA_NO_BUILDER
 int raylua_builder_boot(lua_State *L, FILE *self);
+int raylua_builder_boot_ui(FILE *self);
 #endif
 
 static mz_zip_archive zip_file;
@@ -132,7 +133,8 @@ int main(int argc, const char **argv)
     puts("RAYLUA: No payload.");
     #else
     puts("RAYLUA: No payload, use internal builder.");
-    raylua_builder_boot(L, self);
+    //raylua_builder_boot(L, self);
+    raylua_builder_boot_ui(self);
     #endif
   } else {
     /* Boot on payload. */