Fixed clipping of child windows within parent not taking account of childouter clipping boundaries (including scrollbar, etc.) (#506)

imgui.cpp

@@ -4071,7 +4071,6 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
     clip_rect.Min.y = title_bar_rect.Max.y + window->MenuBarHeight() + 0.5f + border_size;
     clip_rect.Max.x = window->Pos.x + window->Size.x - window->ScrollbarSizes.x - ImMax(border_size, window->WindowPadding.x*0.5f);
     clip_rect.Max.y = window->Pos.y + window->Size.y - border_size - window->ScrollbarSizes.y;
-
     PushClipRect(clip_rect.Min, clip_rect.Max, true);
 
     // Clear 'accessed' flag last thing
@@ -4087,7 +4086,7 @@ bool ImGui::Begin(const char* name, bool* p_opened, const ImVec2& size_on_first_
         window->Collapsed = parent_window && parent_window->Collapsed;
 
         if (!(flags & ImGuiWindowFlags_AlwaysAutoResize) && window->AutoFitFramesX <= 0 && window->AutoFitFramesY <= 0)
-            window->Collapsed |= (window->ClipRect.Min.x >= window->ClipRect.Max.x || window->ClipRect.Min.y >= window->ClipRect.Max.y);
+            window->Collapsed |= (window->ClippedWindowRect.Min.x >= window->ClippedWindowRect.Max.x || window->ClippedWindowRect.Min.y >= window->ClippedWindowRect.Max.y);
 
         // We also hide the window from rendering because we've already added its border to the command list.
         // (we could perform the check earlier in the function but it is simpler at this point)