I had to work with one Xojo created stand Alone application.
The bug is simple: sometimes, when I click (*) in the second windows Listbox, at mouse down; a scroll happens (from where ?) and I usually get the selected Row at some 10 ? 20 ? Rows Before the one I had before the click.
What was I doing and how this happens ?
I had two open windows one (left) where I have to add some information that I drag from the Listbox in the second window.
What happens sometimes is the first window goes frontmost at drop time. The scroll happens in that case.
Also, I use the TouchPad to move to the next Row where I will take some information.
Nota: Ive done that around 300 times (152 target Rows x 2 Columns). I had plenty time to be sure I was not dreaming.
The merge function, in that case, could not be used.
I do not have a single idea on why this happens.
Second strange behavior is
also really strange (It always worked since I wrote it many years ago).
In that project, I can Count the number of days a week (Mon-Sat, excluding Sundays) between two dates. Not a single Row was filled. In that case, I can try the debugger
And I do not talk about the print feature that print or fail depending on from where comes the wind or God knows the reason why (if a reason exists).
Do you know of some virus or ??? that can set some weird stuff ???
PS: this is the project I have so many troubles since
ages 
The project that was in a hard disk I format years ago by error and I use a pdf printed file stored elsewhere to rebuild it from !