Internals: Begin: update ->Hidden flags only on first begin of the frame. (ignore whitespace to see simple diff)

imgui.cpp

@@ -5248,6 +5248,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
     ImGuiWindowFlags flags = window->Flags;
 
     // Ensure that ScrollBar doesn't read last frame's SkipItems
+    IM_ASSERT(window->BeginCount == 0);
     window->SkipItems = false;
 
     // Draw window + handle manual resize
@@ -6029,6 +6030,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     window->BeginCount++;
     g.NextWindowData.ClearFlags();
 
+    // Update visibility
+    if (first_begin_of_the_frame)
+    {
         if (flags & ImGuiWindowFlags_ChildWindow)
         {
             // Child window can be out of sight and have "negative" clip windows.
@@ -6058,8 +6062,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             if (window->AutoFitFramesX <= 0 && window->AutoFitFramesY <= 0 && window->HiddenFramesCannotSkipItems <= 0)
                 skip_items = true;
         window->SkipItems = skip_items;
+    }
 
-    return !skip_items;
+    return !window->SkipItems;
 }
 
 void ImGui::End()