[Lazarus] Keystrokes going awry

[Timothy Groves]

So I wrote a piano program in Lazarus.  It uses keyboard keys to play 
notes.  Specifically, it uses the Q row for white keys, out to the \ key 
(because that's the last one on my keyboard), and the number row for 
black keys, out to the backspace.  FormKeyDown and FormKeyUp are used to 
trap the keystrokes.  KeyPreview := TRUE.

Problem is, some keystrokes are getting trapped earlier, their 7th bit 
set.  [ comes through as #219, ] comes through as #221. Worse, = comes 
through as #187.

Now, I've corrected for all this in my code, but the question is:  
What's causing this?

Running Lazarus 3.4 with fpc 3.2.2 on Debian 12.6, openbox and xfpanel, 
but not xfwm.