message: Begin(): fixed calling Begin() more than once per frame setting `window_just_activated_by_user` which in turn would set Appearing to true for that frame.
diff: @@ -3951,7 +3951,7 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_us
  window_is_new = true;
  }
  - const int current_frame = ImGui::GetFrameCount();
  + const int current_frame = g.FrameCount;
  const bool first_begin_of_the_frame = (window->LastFrameActive != current_frame);
  if (first_begin_of_the_frame)
  window->Flags = (ImGuiWindowFlags)flags;
  @@ -3965,8 +3965,7 @@ bool ImGui::Begin(const char* name, bool* p_open, const ImVec2& size_on_first_us
  CheckStacksSize(window, true);
  IM_ASSERT(parent_window != NULL || !(flags & ImGuiWindowFlags_ChildWindow));
  - // FIXME: This is currently true if we call Begin() multiple times in a row on a same window.
  - bool window_just_activated_by_user = (window->LastFrameActive != current_frame - 1); // Not using !WasActive because the implicit "Debug" window would always toggle off->on
  + bool window_just_activated_by_user = (window->LastFrameActive < current_frame - 1); // Not using !WasActive because the implicit "Debug" window would always toggle off->on
  if (flags & ImGuiWindowFlags_Popup)
  {
  ImGuiPopupRef& popup_ref = g.OpenPopupStack[g.CurrentPopupStack.Size];
  