Please test with xfwm 4.13.x from the Xubuntu QA Experimental PPA:
https://launchpad.net/~xubuntu-dev/+archive/ubuntu/experimental
If the new version does not fix the bug, I suggest that you forward it to the Xfce bug tracker.
https://bugzilla.xfce.org/
Please test with xfwm 4.13.x from the Xubuntu QA Experimental PPA:
https:/ /launchpad. net/~xubuntu- dev/+archive/ ubuntu/ experimental
If the new version does not fix the bug, I suggest that you forward it to the Xfce bug tracker.
https:/ /bugzilla. xfce.org/