message: Begin: Removed asserts that got in the way of some flags combination.
diff: @@ -4659,12 +4659,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
  // Apply minimum/maximum window size constraints and final size
  window->SizeFull = CalcSizeAfterConstraint(window, window->SizeFull);
  - window->Size = window->Collapsed ? window->TitleBarRect().GetSize() : window->SizeFull;
  - if ((flags & ImGuiWindowFlags_ChildWindow) && !(flags & (ImGuiWindowFlags_Popup|ImGuiWindowFlags_Tooltip)))
  - {
  - IM_ASSERT(window_size_x_set_by_api && window_size_y_set_by_api); // Submitted by BeginChild()
  - window->Size = window->SizeFull;
  - }
  + window->Size = window->Collapsed && !(flags & ImGuiWindowFlags_ChildWindow) ? window->TitleBarRect().GetSize() : window->SizeFull;
  // SCROLLBAR STATUS
  