I created a video to demonstrate an AV for the TsListbox using your SkinDemo application. Sometimes this problem appears quickly and other times it takes much manipulation before the error appears (like the video taking 2 minutes). I originally discovered this problem in my application. I then decided to see if this was not my problem only and this confirms that fact.
Also notice that in the listbox item 12 is shown twice although the one on the bottom left appears to be a “ghost”.
I am using your latest build (v15.15) with Delphi Rio.
YouTube video link is: https://youtu.be/YKDUdScZL2w
Thanks.