If you are using XFCE with GDM and are tortured by the “slow keys”-feature after holding down Shift, you might want to take a look at this: bugzilla.redhat.com/show_bug.cgi?id=816764 I don’t remember when I had this problem, but I feel it was sitting around as a draft long enough. I hope this can help someone out there! I can’t test it anymore, since I’ve been using MATE for some time now.