I don't do much GUI editing on Linux, so I can't comment much. But there is currently an issue when using WAYLAND. And from what I hear that is an issue in wayland itself (but, I don't know / and I don't know if that affects your particular case).
Also, the wayland issues may only present in combination with gtk2... If it was that, you might be able to work with QT5. Or by switching to xserver.
Further more, you should at least let us know if your issue is with or without:
- the docked form editor (form editor is a TAB in the source editor)
- anchordocking
As for debugging I have seen some desktop managers that are implemented "synchronous" for all apps together. So if any one app blocks (in certain events), all other block.
=> that means if you set a breakpoint in a mouse/key/paint handler, then that may freeze the entire desktop. Thought that usually happens while the target app is still paused. I don't know about having killed the target app with Ctrl-F2.
However this does not match your description, so this is likely not the issue you have.
If it was: You could try running the IDE *AND* the debugged app with the command line param --sync
It may or may not help.
There is also a chance that you killed a debugged app while it had a lock an the clipboard. Then you might get an issue the moment when you try to use the clipboard (again I have only seen that while the debugged app is paused, not after killing it). So if your editor freeze is on "copy to clipboard" then that may be something to look at.
When you start the ide from a console/terminal then it will print to the terminal.
If you can get the crash (point 1) then it may print useful info. (Hopefully a stacktrace).
As for point 3 (editor freeze after debug)
You could start again from a console, but this time as
gdb lazarus
then enter
r
to run the IDE in gdb.
When it hangs, press ctrl-c in gdb, and enter
bt
that will hopefully report some stacktrace that gives an initial clue what happens.