improve dialog browse, wrap ui task for every Node method that modifies the children list, update the ui every time the scene tree changes, restore fps and stylus state on win, fix bucket tool, fix snapshop restore, init in ui thread

src/util.cpp

@@ -48,6 +48,16 @@ glm::vec4 rect_union(glm::vec4 a, glm::vec4 b)
     return o;
 }
 
+float box_area(glm::vec4 b)
+{
+    return glm::compMul(box_size(b));
+}
+
+glm::vec2 box_size(glm::vec4 b)
+{
+    return zw(b) - xy(b);
+}
+
 // params and returns {min, max} form
 glm::vec4 box_union(glm::vec4 a, glm::vec4 b)
 {