message: Demo: Not using the undesirable Begin() overload.
diff: @@ -2118,7 +2118,8 @@ static void ShowExampleAppConstrainedResize(bool* p_open)
  static void ShowExampleAppFixedOverlay(bool* p_open)
  {
  ImGui::SetNextWindowPos(ImVec2(10,10));
  - if (!ImGui::Begin("Example: Fixed Overlay", p_open, ImVec2(0,0), 0.3f, ImGuiWindowFlags_NoTitleBar|ImGuiWindowFlags_NoResize|ImGuiWindowFlags_NoMove|ImGuiWindowFlags_NoSavedSettings))
  + ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0.0f, 0.0f, 0.0f, 0.3f));
  + if (!ImGui::Begin("Example: Fixed Overlay", p_open, ImGuiWindowFlags_NoTitleBar|ImGuiWindowFlags_NoResize|ImGuiWindowFlags_NoMove|ImGuiWindowFlags_NoSavedSettings))
  {
  ImGui::End();
  return;
  @@ -2127,6 +2128,7 @@ static void ShowExampleAppFixedOverlay(bool* p_open)
  ImGui::Separator();
  ImGui::Text("Mouse Position: (%.1f,%.1f)", ImGui::GetIO().MousePos.x, ImGui::GetIO().MousePos.y);
  ImGui::End();
  + ImGui::PopStyleColor();
  }
  // Demonstrate using "##" and "###" in identifiers to manipulate ID generation.
  