Today (thanks to Cyril Brulebois) I have found bug which in turn was cause by an ever nastier bug in URandR. The current refresh of a device was detected even if such device was not enabled (???) (i.e. plugged in but disabled). URandR knows that, if a device has a current refresh rate, such device must necessarily be enabled (otherwise the said refresh rate wouldn’t be called “current”).
The cause of this problem was so stupid that I’m sure it was the result of one of my late night coding sessions :-/
Please let me know if you have problems with this new release.