Docking: Fix handling of WindowMenuButtonPosition == ImGuiDir_None in Docking Nodes. (#3499)

imgui.cpp

@@ -13254,7 +13254,7 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
     node->IsFocused = is_focused;
 
     const ImGuiDockNodeFlags node_flags = node->GetMergedFlags();
-    const bool has_window_menu_button = (node_flags & ImGuiDockNodeFlags_NoWindowMenuButton) == 0;
+    const bool has_window_menu_button = (node_flags & ImGuiDockNodeFlags_NoWindowMenuButton) == 0 && (style.WindowMenuButtonPosition != ImGuiDir_None);
     const bool has_close_button = (node_flags & ImGuiDockNodeFlags_NoCloseButton) == 0;
 
     // In a dock node, the Collapse Button turns into the Window Menu button.