Since upgrading to 3022, I noticed that my breakpoints were getting a
proper "check" mark when I initially started debugging, but were almost
immediately changing to an X. I tried rebuilding my project, clearing
the classes dir, moving the output classes dir, checking and rechecking
the "Generate Debugging Info Box", but nothing worked. Finally, I was
able to fix things by - of all things - clearing the "Generate Debugging
Info" box and then trying to debug with a fresh classes dir. This
worked fine! I then re-enabled it and debugged, and it still works.
However, once I cleared the box AND cleared the classes cache, I finally
got the expected behavior.
This smells like a bug, but I wanted to post here mostly to help anyone
else with this problem.