TAdvSearchComboBox How to implement clRed BorderColor when Text not in Items?

I am trying to implement a Red Bordercolor for invalid entries on the TAdvSearchComboBox.
I tried adding events to OnChange, OnExit, OnSelect and OnKeypress that execute the following code:

With AdvSearchComboBox1 do
var valid : boolean;
valid := (Items.IndexOf(Text) <> -1);

var NewColor : TColor;
if valid then
  NewColor := clGreen
  NewColor := clRed;

if BorderColor <> NewColor then
  BorderColor := NewColor;
  Color := NewColor;
  result := true;


Still it does not work fully reliable, when i first enter a partial text, select it from the dropdown, the red color remains.

How to best implement this?

Thanks in advance

We applied an improvement to make this work better.
This improvement will be applied in the next update.