Window: fixed child window sizing lag + minimum size clamping lag

imgui.cpp

@@ -3465,7 +3465,11 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
 
         // Minimum window size
         if (!(flags & ImGuiWindowFlags_ChildWindow) && !(flags & ImGuiWindowFlags_Tooltip))
+        {
             window->SizeFull = ImMax(window->SizeFull, style.WindowMinSize);
+            if (!window->Collapsed)
+                window->Size = window->SizeFull;
+        }
 
         // POSITION
 
@@ -3475,7 +3479,7 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
         if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & ImGuiWindowFlags_Popup))
         {
             window->Pos = window->PosFloat = parent_window->DC.CursorPos;
-            window->SizeFull = size_on_first_use; // NB: argument name 'size_on_first_use' misleading here, it's really just 'size' as provided by user.
+            window->Size = window->SizeFull = size_on_first_use; // NB: argument name 'size_on_first_use' misleading here, it's really just 'size' as provided by user.
         }
 
         // Position popup