diff --git a/game/src/ui/uiman.c b/game/src/ui/uiman.c
index 647907b..cd088b3 100644
--- a/game/src/ui/uiman.c
+++ b/game/src/ui/uiman.c
@@ -14,7 +14,7 @@ extern vec3 camera_position;
 static Widget *ui_root;
 static mat4 projection;
 
-static Widget *hovered_widget, *clicked_widget;
+static Widget *hovered_widget = NULL;
 
 void
 uiman_init ()
@@ -25,7 +25,7 @@ uiman_init ()
   glm_ortho (0.0, (float) sdl_window_w, (float) sdl_window_h, 0.0, -1.0, 1.0, projection);
 
   Widget *debug_menu = Widget_container_new (FALSE, 8, 4);
-  Widget_set_background_image (debug_menu, RESTEX ("terrain4"));
+  debug_menu->background_image = RESTEX ("terrain4");
   VEC2_SETI (debug_menu->position, 32, 32);
   VEC2_SETI (debug_menu->size, 350, 170);
   debug_menu->border_width = 4;
@@ -50,11 +50,11 @@ uiman_init ()
   Widget_add_child_weighed (debug_menu, chkboxes, 1);
 
   Widget *content = Widget_plain_new ();
-  Widget_set_background_image (content, RESTEX ("terrain1"));
+  content->background_image = RESTEX ("terrain1");
   VEC2_SETI (content->size, 400, 600);
   
   Widget *scrollable_window = Widget_composite_scrollable_make (content);
-  Widget_set_background_image (scrollable_window, RESTEX ("terrain4"));
+  scrollable_window->background_image = RESTEX ("terrain4");
   VEC2_SETI (scrollable_window->position, 390, 32);
   VEC2_SETI (scrollable_window->size, 350, 350);
   scrollable_window->border_width = 4;
@@ -109,23 +109,28 @@ uiman_cb_key_up (SDL_Event *event, void *data)
 gboolean
 uiman_cb_mouse_motion (SDL_Event *event, void *data)
 {
-  UNUSED (data);
+  UNUSED (event, data);
 
-  Widget *new_hover = Widget_find_xy (ui_root, (vec2) { event->motion.x, event->motion.y });
+  Widget *widget = Widget_find_xy (ui_root, (vec2) { event->motion.x, event->motion.y });
 
-  if (new_hover != hovered_widget)
+  if (widget != hovered_widget)
     {
-      if (hovered_widget)
+      if (hovered_widget && hovered_widget->on_mouse_leave)
 	{
-	  hovered_widget->hovered = FALSE;
+	  hovered_widget->on_mouse_leave (hovered_widget, hovered_widget->mouse_leave_data);
 	}
       
-      if (new_hover)
+      if (widget && widget->on_mouse_enter)
 	{
-	  new_hover->hovered = TRUE;
+	  widget->on_mouse_enter (widget, widget->mouse_enter_data);
 	}
       
-      hovered_widget = new_hover;
+      hovered_widget = widget;
+    }
+
+  if (hovered_widget && hovered_widget->on_mouse_move)
+    {
+      hovered_widget->on_mouse_move (hovered_widget, hovered_widget->mouse_move_data);
     }
   
   /* This callback always eats the event, because why would the game
@@ -133,55 +138,25 @@ uiman_cb_mouse_motion (SDL_Event *event, void *data)
   return TRUE;
 }
 
+gboolean widget_match_bdown (Widget *self) { return self->on_left_down || self->on_right_down; };
 gboolean
 uiman_cb_button_down (SDL_Event *event, void *data)
 {
   UNUSED (data);
-
-  Widget *new_clicked = Widget_find_xy (ui_root, (vec2) { event->motion.x, event->motion.y });
   
-  if (new_clicked != clicked_widget)
-    {
-      if (clicked_widget && (clicked_widget->on_left_click || clicked_widget->on_right_click))
-	{
-	  clicked_widget->clicked = FALSE;
-	}
+  Widget *widget = Widget_find_xy_matching (ui_root, (vec2) { event->button.x, event->button.y }, widget_match_bdown);
 
-      if (new_clicked && (new_clicked->on_left_click || new_clicked->on_right_click))
-	{
-	  new_clicked->clicked = TRUE;
-	}
-      
-      clicked_widget = new_clicked;
-    }
-  
-  return TRUE;
-}
-
-gboolean
-uiman_cb_button_up (SDL_Event *event, void *data)
-{
-  UNUSED (data);
-
-  Widget *widget = Widget_find_xy (ui_root, (vec2) { event->motion.x, event->motion.y });
-
-  if (clicked_widget)
-    {
-      clicked_widget->clicked = FALSE;
-      clicked_widget = NULL;
-    }
-  
   if (widget)
     {
-      if (event->button.button == SDL_BUTTON_LEFT && widget->on_left_click)
+      if (event->button.button == SDL_BUTTON_LEFT && widget->on_left_down)
 	{
-	  widget->on_left_click (widget, widget->left_click_data);
+	  widget->on_left_down (widget, widget->left_down_data);
 	  return TRUE;
 	}
 
-      if (event->button.button == SDL_BUTTON_RIGHT && widget->on_right_click)
+      if (event->button.button == SDL_BUTTON_RIGHT && widget->on_right_down)
 	{
-	  widget->on_right_click (widget, widget->right_click_data);
+	  widget->on_right_down (widget, widget->right_down_data);
 	  return TRUE;
 	}
     }
@@ -189,10 +164,58 @@ uiman_cb_button_up (SDL_Event *event, void *data)
   return FALSE;
 }
 
+gboolean widget_match_bup (Widget *self) { return self->on_left_up || self->on_right_up; };
+gboolean
+uiman_cb_button_up (SDL_Event *event, void *data)
+{
+  UNUSED (data);
+
+  Widget *widget = Widget_find_xy_matching (ui_root, (vec2) { event->button.x, event->button.y }, widget_match_bup);
+
+  if (widget)
+    {
+      if (event->button.button == SDL_BUTTON_LEFT && widget->on_left_up)
+	{
+	  widget->on_left_up (widget, widget->left_up_data);
+	  return TRUE;
+	}
+
+      if (event->button.button == SDL_BUTTON_RIGHT && widget->on_right_up)
+	{
+	  widget->on_right_up (widget, widget->right_up_data);
+	  return TRUE;
+	}
+    }
+  
+  return FALSE;
+}
+
+gboolean widget_match_scroll (Widget *self) { return self->on_scroll_down || self->on_scroll_up; };
 gboolean
 uiman_cb_mouse_wheel (SDL_Event *event, void *data)
 {
   UNUSED (event, data);
+
+  Widget *widget = Widget_find_xy_matching (ui_root, (vec2) { event->wheel.mouse_x, event->wheel.mouse_y }, widget_match_scroll);
+
+  if (widget)
+    {
+      if (event->wheel.y > 0)
+	{
+	  if (widget->on_scroll_up)
+	    {
+	      widget->on_scroll_up (widget, widget->scroll_up_data);
+	    }
+	}
+      else
+	{
+	  if (widget->on_scroll_down)
+	    {
+	      widget->on_scroll_down (widget, widget->scroll_down_data);
+	    }
+	}
+    }
+  
   return FALSE;
 }
 
diff --git a/game/src/ui/widget.c b/game/src/ui/widget.c
index 63fc19c..5cdf04c 100644
--- a/game/src/ui/widget.c
+++ b/game/src/ui/widget.c
@@ -11,6 +11,7 @@ ui_el_new_internal (WidgetKind kind)
   e->kind = kind;
   e->visible = true;
   e->children = g_array_new (false, false, sizeof (Widget *));
+  e->icon = ICON_NONE;
   glm_vec4_zero (e->background_color);
   return e;
 }
@@ -78,20 +79,6 @@ Widget_add_child_weighed (Widget *parent, Widget *child, float layout_weight)
   Widget_add_child (parent, child);
 }
 
-void
-Widget_set_icon (Widget *widget, WidgetIcon icon)
-{
-  widget->has_icon = TRUE;
-  widget->icon = icon;
-}
-
-void
-Widget_set_background_image (Widget *widget, unsigned int image)
-{
-  widget->has_background_image = TRUE;
-  widget->background_image = image;
-}
-
 void
 Widget_set_on_tick (Widget *widget,
 		    void (*on_tick) (Widget *, void *),
@@ -102,12 +89,12 @@ Widget_set_on_tick (Widget *widget,
 }
 
 void
-Widget_set_on_left_click (Widget *widget,
-			  void (*on_left_click) (Widget *, void *),
-			  void *userdata)
+Widget_set_on_left_up (Widget *widget,
+		       void (*on_left_up) (Widget *, void *),
+		       void *userdata)
 {
-  widget->on_left_click = on_left_click;
-  widget->left_click_data = userdata;
+  widget->on_left_up = on_left_up;
+  widget->left_up_data = userdata;
 }
 
 void
@@ -153,13 +140,18 @@ Widget_hit_test (Widget *widget, vec2 point)
 }
 
 Widget *
-Widget_find_xy (Widget *widget, vec2 pos)
+Widget_find_xy_matching (Widget *widget, vec2 pos, gboolean (*match_fn) (Widget *widget))
 {
   if (!widget->visible)
     {
       return NULL;
     }
 
+  if (!Widget_hit_test (widget, pos))
+    {
+      return NULL;
+    }
+  
   vec2 pos_scrolled;
   glm_vec2_copy (pos, pos_scrolled);
   
@@ -168,15 +160,10 @@ Widget_find_xy (Widget *widget, vec2 pos)
       glm_vec2_add (pos_scrolled, widget->scrollable.scroll_position, pos_scrolled);
     }
 
-  if (!Widget_hit_test (widget, pos_scrolled))
-    {
-      return NULL;
-    }
-  
   for (int i = widget->children->len - 1; i >= 0; --i)
     {
       Widget *child = g_array_index (widget->children, Widget *, i);
-      Widget *found = Widget_find_xy (child, pos_scrolled);
+      Widget *found = Widget_find_xy_matching (child, pos_scrolled, match_fn);
       
       if (found != NULL)
 	{
@@ -184,7 +171,18 @@ Widget_find_xy (Widget *widget, vec2 pos)
 	}
     }
 
-  return widget;
+  if (!match_fn || match_fn (widget))
+    {
+      return widget;
+    }
+
+  return NULL;
+}
+
+Widget *
+Widget_find_xy (Widget *widget, vec2 pos)
+{
+  return Widget_find_xy_matching (widget, pos, NULL);
 }
 
 void
@@ -410,21 +408,12 @@ Widget_render (Widget *widget, mat4 projection, int window_height)
   program_set_vec4 (RESPRG ("uiwidget"), "border_color", widget->border_color);
   program_set_vec2 (RESPRG ("uiwidget"), "widget_size", widget->size);
 
-  program_set_int (RESPRG ("uiwidget"), "has_background_image", widget->has_background_image);
+  program_set_int (RESPRG ("uiwidget"), "has_background_image", widget->background_image != 0);
   texture_use (widget->background_image, 0); /* If it doesn't have a texture, it'll be 0 anyway. */
 
   program_set_vec4 (RESPRG ("uiwidget"), "background_color", widget->background_color);
-  
-  if (widget->clicked)
-    {
-      program_set_vec4 (RESPRG ("uiwidget"), "background_color", widget->clicked_bg_color);
-    }
-  else if (widget->hovered)
-    {
-      program_set_vec4 (RESPRG ("uiwidget"), "background_color", widget->hovered_bg_color);
-    }
 
-  program_set_int (RESPRG ("uiwidget"), "has_icon", widget->has_icon);
+  program_set_int (RESPRG ("uiwidget"), "has_icon", widget->icon != -1);
   program_set_float (RESPRG ("uiwidget"), "icon_index", widget->icon);
   texture_use (RESTEX ("icons"), 1);
 
@@ -603,6 +592,78 @@ uicb_scrollable_scroll_right (Widget *self, void *userdata)
   Widget_scrollable_scroll (scrollable, (vec2) { 1.0, 0.0 });
 }
 
+void
+uicb_scrollbar_start_scroll (Widget *self, void *userdata)
+{
+  UNUSED (userdata);
+
+  Widget *scr = self->scrollbar.scrollable;
+  vec2 mouse_pos;
+  SDL_GetMouseState ((float*)&mouse_pos[0], (float*)&mouse_pos[1]);
+
+  unsigned int idx = self->scrollbar.horizontal ? 0 : 1;
+
+  float content_size = scr->scrollable.content_size[idx];
+  float view_size    = scr->size[idx];
+  float track_pixels = self->size[idx];
+
+  float thumb_size_norm = view_size / content_size;
+  float thumb_pixels    = thumb_size_norm * track_pixels;
+
+  float max_scroll     = content_size - view_size;
+  float thumb_pos_norm = max_scroll > 0.0f
+      ? scr->scrollable.scroll_position[idx] / max_scroll
+      : 0.0f;
+
+  float thumb_start_px = thumb_pos_norm * (track_pixels - thumb_pixels);
+
+  float click_axis  = self->scrollbar.horizontal ? mouse_pos[0] : mouse_pos[1];
+  float track_start = self->scrollbar.horizontal
+      ? self->position[0]
+      : self->position[1];
+
+  self->scrollbar.drag_offset = click_axis - track_start - thumb_start_px;
+  self->scrollbar.dragging    = TRUE;
+}
+
+void
+uicb_scrollbar_scroll (Widget *self, void *userdata)
+{
+  UNUSED (userdata);
+
+  if (self->scrollbar.dragging == FALSE)
+    {
+      return;
+    }
+  
+  Widget *scr = self->scrollbar.scrollable;
+  vec2 mouse_pos;
+  SDL_GetMouseState((float*) &mouse_pos[0], (float*) &mouse_pos[1]);
+
+  unsigned int idx = self->scrollbar.horizontal ? 0 : 1;
+  float content_size  = scr->scrollable.content_size[idx];
+  float view_size     = scr->size[idx];
+  float track_pixels  = self->size[idx];
+
+  float click_axis = self->scrollbar.horizontal ? mouse_pos[0] : mouse_pos[1];
+  float track_start = self->scrollbar.horizontal ? self->position[0] : self->position[1];
+  
+  float t = (click_axis - track_start - self->scrollbar.drag_offset)
+            / track_pixels;
+  t = glm_clamp (t, 0.0f, 1.0f);
+
+  float max_scroll = content_size - view_size;
+  scr->scrollable.scroll_position[idx] =
+    glm_clamp (t * content_size, 0.0f, max_scroll > 0.0f ? max_scroll : 0.0f);
+}
+
+void
+uicb_scrollbar_stop_scroll (Widget *self, void *userdata)
+{
+  UNUSED (userdata);
+  self->scrollbar.dragging = FALSE;
+}
+
 Widget *
 Widget_label_make_int (const char *fmt, int *ptr, TextAlignment alignment)
 {
@@ -627,11 +688,11 @@ Widget_composite_spinner_make_int (const char *fmt, int *ptr)
   Widget *label = Widget_label_make_int (fmt, ptr, TEXT_ALIGN_CENTER);
   Widget *right = Widget_plain_new ();
 
-  Widget_set_on_left_click (left, uicb_decrement_int, ptr);
-  Widget_set_icon (left, ICON_SPINNER_LEFT);
+  Widget_set_on_left_up (left, uicb_decrement_int, ptr);
+  left->icon = ICON_SPINNER_LEFT;
   left->aspect_ratio = 1.0;
-  Widget_set_on_left_click (right, uicb_increment_int, ptr);
-  Widget_set_icon (right, ICON_SPINNER_RIGHT);
+  Widget_set_on_left_up (right, uicb_increment_int, ptr);
+  right->icon = ICON_SPINNER_RIGHT;
   right->aspect_ratio = 1.0;
 
   Widget_add_child_weighed (cont, left, 1);
@@ -649,10 +710,10 @@ Widget_composite_checkbox_make (const char *label, char *flag)
   Widget *cont = Widget_container_new (TRUE, 0, 8);
   Widget *box = Widget_plain_new ();
 
-  Widget_set_icon (box, ICON_CHECKBOX_UNCHECKED);
+  box->icon = ICON_CHECKBOX_UNCHECKED;
   box->aspect_ratio = 1.0;
   Widget_set_on_tick (box, uicb_checkbox_show_flag, flag);
-  Widget_set_on_left_click (box, uicb_switch_flag, flag);
+  Widget_set_on_left_up (box, uicb_switch_flag, flag);
 
   Widget_add_child_weighed (cont, box, 1);
   Widget_add_child_weighed (cont, Widget_label_new (label, TEXT_ALIGN_LEFT), 1);
@@ -666,23 +727,34 @@ Widget_composite_scrollable_make (Widget *content)
   Widget *cont_main = Widget_container_new (FALSE, 8, 4);
   Widget *scrollable = Widget_scrollable_new ();
   Widget_add_child (scrollable, content);
+
+  scrollable->on_scroll_down = uicb_scrollable_scroll_down;
+  scrollable->scroll_down_data = scrollable;
+  scrollable->on_scroll_up = uicb_scrollable_scroll_up;
+  scrollable->scroll_up_data = scrollable;
   
   Widget *scroll_up = Widget_plain_new ();
   Widget *scroll_down = Widget_plain_new ();
 
-  Widget_set_icon (scroll_up, ICON_ARROW_UP);
-  Widget_set_on_left_click (scroll_up, uicb_scrollable_scroll_up, scrollable);
+  scroll_up->icon = ICON_ARROW_UP;
+  Widget_set_on_left_up (scroll_up, uicb_scrollable_scroll_up, scrollable);
   scroll_up->aspect_ratio = 1.0;
 
-  Widget_set_icon (scroll_down, ICON_ARROW_DOWN);
-  Widget_set_on_left_click (scroll_down, uicb_scrollable_scroll_down, scrollable);
+  scroll_down->icon = ICON_ARROW_DOWN;
+  Widget_set_on_left_up (scroll_down, uicb_scrollable_scroll_down, scrollable);
   scroll_down->aspect_ratio = 1.0;
 
   Widget *cont_horiz = Widget_container_new (TRUE, 0, 4);
   Widget *scrollbar_vertical = Widget_container_new (FALSE, 0, 0);
+  Widget *actual_scrollbar_vertical = Widget_scrollbar_new (scrollable, FALSE);
+  
+  actual_scrollbar_vertical->on_left_down = uicb_scrollbar_start_scroll;
+  actual_scrollbar_vertical->on_left_up = uicb_scrollbar_stop_scroll;
+  actual_scrollbar_vertical->on_mouse_leave = uicb_scrollbar_stop_scroll;
+  actual_scrollbar_vertical->on_mouse_move = uicb_scrollbar_scroll;
 
   Widget_add_child_weighed (scrollbar_vertical, scroll_up, 1);
-  Widget_add_child_weighed (scrollbar_vertical, Widget_scrollbar_new (scrollable, FALSE), 1);
+  Widget_add_child_weighed (scrollbar_vertical, actual_scrollbar_vertical, 1);
   Widget_add_child_weighed (scrollbar_vertical, scroll_down, 1);
 
   Widget_add_child_weighed (cont_horiz, scrollable, 0.93);
@@ -693,21 +765,27 @@ Widget_composite_scrollable_make (Widget *content)
   Widget *scroll_left = Widget_plain_new ();
   Widget *scroll_right = Widget_plain_new ();
 
-  Widget_set_icon (scroll_left, ICON_ARROW_LEFT);
-  Widget_set_on_left_click (scroll_left, uicb_scrollable_scroll_left, scrollable);
+  scroll_left->icon = ICON_ARROW_LEFT;
+  Widget_set_on_left_up (scroll_left, uicb_scrollable_scroll_left, scrollable);
   scroll_left->aspect_ratio = 1.0;
 
-  Widget_set_icon (scroll_right, ICON_ARROW_RIGHT);
-  Widget_set_on_left_click (scroll_right, uicb_scrollable_scroll_right, scrollable);
+  scroll_right->icon = ICON_ARROW_RIGHT;
+  Widget_set_on_left_up (scroll_right, uicb_scrollable_scroll_right, scrollable);
   scroll_right->aspect_ratio = 1.0;
 
   Widget *scrollbar_horizontal = Widget_container_new (TRUE, 0, 0);
+  Widget *actual_scrollbar_horizontal = Widget_scrollbar_new (scrollable, TRUE);
 
+  actual_scrollbar_horizontal->on_left_down = uicb_scrollbar_start_scroll;
+  actual_scrollbar_horizontal->on_left_up = uicb_scrollbar_stop_scroll;
+  actual_scrollbar_horizontal->on_mouse_leave = uicb_scrollbar_stop_scroll;
+  actual_scrollbar_horizontal->on_mouse_move = uicb_scrollbar_scroll;
+  
   Widget *padding = Widget_plain_new ();
   padding->aspect_ratio = 1.0;
   
   Widget_add_child_weighed (scrollbar_horizontal, scroll_left, 1);
-  Widget_add_child_weighed (scrollbar_horizontal, Widget_scrollbar_new (scrollable, TRUE), 1);
+  Widget_add_child_weighed (scrollbar_horizontal, actual_scrollbar_horizontal, 1);
   Widget_add_child_weighed (scrollbar_horizontal, scroll_right, 1);
   Widget_add_child_weighed (scrollbar_horizontal, padding, 1);
 
diff --git a/game/src/ui/widget.h b/game/src/ui/widget.h
index 6363a04..cf35930 100644
--- a/game/src/ui/widget.h
+++ b/game/src/ui/widget.h
@@ -24,6 +24,7 @@ typedef enum WidgetKind
 
 typedef enum WidgetIcon
   {
+    ICON_NONE = -1,
     ICON_CHECKBOX_UNCHECKED = 0,
     ICON_CHECKBOX_CHECKED,
     ICON_SPINNER_LEFT,
@@ -64,9 +65,11 @@ typedef struct ScrollableWidget
 
 typedef struct ScrollbarWidget
 {
-  struct Widget *scrollable;
+  struct Widget *scrollable;	/* Rename to target. */
   gboolean horizontal;
-  float bar_size;
+  /* Used for input. */
+  gboolean dragging;
+  float drag_offset;
 } ScrollbarWidget;
 
 typedef struct Widget
@@ -83,30 +86,40 @@ typedef struct Widget
   };
 
   gboolean visible;
-  gboolean hovered, clicked;
-  
+
   vec2 position;
   vec2 size;
   float layout_weight;
   float aspect_ratio;
   
   vec4 background_color;
-  vec4 hovered_bg_color;
-  vec4 clicked_bg_color;
-  
-  gboolean has_background_image;
   unsigned int background_image;
-
-  gboolean has_icon;
   WidgetIcon icon;
 
   float border_width;
   vec4 border_color;
 
-  void (*on_left_click) (struct Widget *, void *);
-  void *left_click_data;
-  void (*on_right_click) (struct Widget *, void *);
-  void *right_click_data;
+  void (*on_left_down) (struct Widget *, void *);
+  void *left_down_data;
+  void (*on_left_up) (struct Widget *, void *);
+  void *left_up_data;
+  void (*on_right_down) (struct Widget *, void *);
+  void *right_down_data;
+  void (*on_right_up) (struct Widget *, void *);
+  void *right_up_data;
+
+  void (*on_mouse_enter) (struct Widget *, void *);
+  void *mouse_enter_data;
+  void (*on_mouse_leave) (struct Widget *, void *);
+  void *mouse_leave_data;
+  void (*on_mouse_move) (struct Widget *, void *);
+  void *mouse_move_data;
+  
+  void (*on_scroll_down) (struct Widget *, void *);
+  void *scroll_down_data;
+  void (*on_scroll_up) (struct Widget *, void *);
+  void *scroll_up_data;
+  
   void (*on_tick) (struct Widget *, void *);
   void *tick_data;
 } Widget;
@@ -121,16 +134,15 @@ void Widget_add_child (Widget *parent, Widget *child);
 void Widget_add_child_weighed (Widget *parent, Widget *child,
 			       float layout_weight);
 
-void Widget_set_background_image (Widget *widget, unsigned int image);
-void Widget_set_icon (Widget *widget, WidgetIcon icon);
 void Widget_set_on_tick (Widget *widget, void (*on_tick) (Widget *, void *), void *userdata);
-void Widget_set_on_left_click (Widget *widget, void (*on_left_click) (Widget *, void *), void *userdata);
+void Widget_set_on_left_up (Widget *widget, void (*on_left_up) (Widget *, void *), void *userdata);
 
 void Widget_label_set_text (Widget *widget, const char *text);
 void Widget_label_printf (Widget *widget, const char *format, ...);
 
 void Widget_scrollable_scroll (Widget *widget, vec2 direction);
 
+Widget *Widget_find_xy_matching (Widget *widget, vec2 pos, gboolean (*match_fn) (Widget *widget));
 Widget *Widget_find_xy (Widget *widget, vec2 point);
 
 void ui_widget_mesh_init ();
@@ -162,6 +174,10 @@ void uicb_scrollable_scroll_up (Widget *self, void *userdata);
 void uicb_scrollable_scroll_left (Widget *self, void *userdata);
 void uicb_scrollable_scroll_right (Widget *self, void *userdata);
 
+void uicb_scrollbar_start_scroll (Widget *self, void *userdata);
+void uicb_scrollbar_scroll (Widget *self, void *userdata);
+void uicb_scrollbar_stop_scroll (Widget *self, void *userdata);
+
 Widget *Widget_label_make_int (const char *fmt, int *ptr, TextAlignment alignment);
 Widget *Widget_label_make_float (const char *fmt, float *ptr, TextAlignment alignment);