TAdvComboBox: strange problem

VCL TMS VCL UI Pack
1

TComboBox works properly.
Items is created statically - at design time.

  public
    LastGroup: TList<TAdvComboBox>;
...
  LastGroup := TList<TAdvComboBox>.Create;
  LastGroup.Add(advcbxLastGroup01);
...
// In the class
procedure TRoundNew.GetGrData;
      FGrData.Last.LastGroup := Frm.LastGroup[I].ItemIndex

No error, inaccessible value...
Items.IndexOf(..) didn't help either.
I tested title and text. They are fine.

This did the trick.

  var AA: TAdvComboBox;
  AA := Frm.LastGroup[I];
      FGrData.Last.LastGroup := AA.ItemIndex;

FootMan_-Delphi_11-Round_Stopped-_Thread_17488_Built 2023 05 07 19 19 00

2

I'm not sure what

FGrData.Last.LastGroup := Frm.LastGroup[I].ItemIndex

is expected to do?

I retested accessing the TAdvComboBox via a generic list but I couldn't see any issue here.

var
  LastGroup: TList<TAdvComboBox>;
begin
  LastGroup := TList<TAdvComboBox>.Create;
  LastGroup.Add(advcombobox1);

  LastGroup[0].ItemIndex := 2;

  caption := LastGroup[0].ItemIndex.ToString;

end;
3

I expect an ItemIndex value. As you can see in the attached image, the first line, so returns "nothing".
Your test example is about something else.

4

Then please provide full source project with which we can reproduce this issue as well as details about Delphi version used.