message: Begin: Fix border size latch when rounding uses Child or Popup value.
diff: @@ -4272,15 +4272,15 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
  }
  }
  - // Lock window padding so that altering the border sizes for children doesn't have side-effects.
  - window->WindowPadding = style.WindowPadding;
  - if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_AlwaysUseWindowPadding | ImGuiWindowFlags_ComboBox | ImGuiWindowFlags_Popup)) && style.WindowBorderSize == 0.0f)
  - window->WindowPadding = ImVec2(0.0f, (flags & ImGuiWindowFlags_MenuBar) ? style.WindowPadding.y : 0.0f);
  + // Lock window rounding, border size and rounding so that altering the border sizes for children doesn't have side-effects.
  window->WindowRounding = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildRounding : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupRounding : style.WindowRounding;
  window->WindowBorderSize = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildBorderSize : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupBorderSize : style.WindowBorderSize;
  - const ImVec2 window_padding = window->WindowPadding;
  + window->WindowPadding = style.WindowPadding;
  + if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_AlwaysUseWindowPadding | ImGuiWindowFlags_ComboBox | ImGuiWindowFlags_Popup)) && window->WindowBorderSize == 0.0f)
  + window->WindowPadding = ImVec2(0.0f, (flags & ImGuiWindowFlags_MenuBar) ? style.WindowPadding.y : 0.0f);
  const float window_rounding = window->WindowRounding;
  const float window_border_size = window->WindowBorderSize;
  + const ImVec2 window_padding = window->WindowPadding;
  // Calculate auto-fit size, handle automatic resize
  const ImVec2 size_auto_fit = CalcSizeAutoFit(window);
  