message: Child window with MenuBar use regular WindowPadding.y so layout look consistent in child or in a regular window.
diff: @@ -4253,7 +4253,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
  }
  // Lock window padding so that altering the ShowBorders flag for children doesn't have side-effects.
  - window->WindowPadding = ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_AlwaysUseWindowPadding | ImGuiWindowFlags_ShowBorders | ImGuiWindowFlags_ComboBox | ImGuiWindowFlags_Popup))) ? ImVec2(0,0) : style.WindowPadding;
  + window->WindowPadding = style.WindowPadding;
  + if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_AlwaysUseWindowPadding | ImGuiWindowFlags_ShowBorders | ImGuiWindowFlags_ComboBox | ImGuiWindowFlags_Popup)))
  + window->WindowPadding = ImVec2(0.0f, (flags & ImGuiWindowFlags_MenuBar) ? style.WindowPadding.y : 0.0f);
  // Calculate auto-fit size, handle automatic resize
  const ImVec2 size_auto_fit = CalcSizeAutoFit(window);
  