message: Reapply patch from imgui bug number 1345
diff: @@ -4292,7 +4292,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
  // Apply minimum/maximum window size constraints and final size
  window->SizeFull = CalcSizeFullWithConstraint(window, window->SizeFull);
  window->Size = window->Collapsed ? window->TitleBarRect().GetSize() : window->SizeFull;
  - if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & ImGuiWindowFlags_Popup))
  + if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_Popup|ImGuiWindowFlags_Tooltip)))
  {
  IM_ASSERT(window_size_set_by_api); // Submitted by BeginChild()
  window->Size = window->SizeFull;
  @@ -4319,11 +4319,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
  window->OrderWithinParent = parent_window->DC.ChildWindows.Size;
  parent_window->DC.ChildWindows.push_back(window);
  }
  - if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_Popup|ImGuiWindowFlags_Tooltip)))
  - {
  - IM_ASSERT(window_size_set_by_api); // Submitted by BeginChild()
  + if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_Popup|ImGuiWindowFlags_Tooltip)) && !window_pos_set_by_api)
  window->Pos = window->PosFloat = parent_window->DC.CursorPos;
  - }
  const bool window_pos_with_pivot = (window->SetWindowPosVal.x != FLT_MAX && window->HiddenFrames == 0);
  if (window_pos_with_pivot)
  