This is about a program I used for some years and wrote it myself.
In short, a form with a filelistbox, the entries are clickable. When selected an entry, a second form draws a figure.
In the past, not sure about when I used it last time, I could select an entry in the list and put my finger on the up or down key
and then the list was scrolled up or down and each entry would "OnChange" draw a figure.
Very funny to see all the figures flashing by...
( The figures are airfoil profiles if it matters to you , drawn from a coordinate list )
This ran for a long time fine, on linux mint.
But now the background pops up between the selections and the focus is lost.
So now the every 2 or 10 "changes" in the list the focus is lost and I need to click on some entry to start scolling again.
For some reason I think linux mint is causing the problem but I cannot be sure about it.
Does someone recognise this behaivior ?