The key quote from the OP as to whether this is still an issue is:
No I haven't. I've not had this problem in weeks, so I see no reason
why I need to tinker with it, for now.
To diagnose this types of issues first a simple check is to see if a theme or other configuration causes this issue.
Thus the question:
Is this behaviour user specific? Try creating a new user account and
log into that.
If by creating a new user and the issue still occurs then the problem is highly likely to be either a graphical issue and/or a compiz issue.
Both of these issues should be reported as a bug report.
It would be helpful in such a report to looks at posting the contents of
/var/log/Xorg.0.log. Often you can see what the issue is by looking for errors in this log.
In conclusion - the OP states this has not occurred for weeks. Its highly likely an update (graphical related or compiz related) has resolved this question.