Check /home/YOURUSER/.xsession-errors or /home/YOURUSER/.xsession-errors.old for relevant error messages. Post them here. Take care as this log can frequently contain sensitive information logged by some applications.
You could try creating a new user on the computer and try reproducing the problem with it. If the problem does not happen then it could be some settings under your other account. -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org