I had the same issue for a long time in 14.04 at least together with kernel 4.2 (and very likely 3.19 and maybe even before if I remember right).
It is still not fixed in ubuntu 16.04, kernel 4.4.0-28-generic. I get this problem mostly after suspend. But I rarely get the invisible characters also during a normal session when I click something (about every few days). I could not yet reproduce if it depends on the object I click or if there is a pattern to reproduce it. Tested hardware: Latitude E5510, CPU/GPU Intel core i5 520M, using the on-chip graphics. I have an PR02X docking station and a dual monitor setup (2x external BenQ GW2460 via DVI) when this error happens. The problem does not occor when using the internal monitor of the laptop only. Please note that my on-chip-GPU can handle two monitors only. Basically that means that the internal monitor is switched off automatically as soon as I use the two external monitors. So far this is working fine, however. uname -a Linux lat61 4.4.0-28-generic #47-Ubuntu SMP Fri Jun 24 10:09:13 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1528843 Title: Fonts missing after suspend Status in xorg package in Ubuntu: Expired Bug description: After resuming from suspend cairo-dock disappears and all gnome applications show only the letters "s" and """. The rest of the letters is blank. Hope I still manage to file a bug report and to run apport-collect on it. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: xorg 1:7.7+12ubuntu1 Uname: Linux 4.4.0-040400rc5-lowlatency x86_64 ApportVersion: 2.19.3-0ubuntu2 Architecture: amd64 CurrentDesktop: Unity Date: Wed Dec 23 13:46:41 2015 EcryptfsInUse: Yes SourcePackage: xorg Symptom: display UpgradeStatus: No upgrade log present (probably fresh install) --- ApportVersion: 2.19.3-0ubuntu2 Architecture: amd64 DistroRelease: Ubuntu 16.04 EcryptfsInUse: Yes Package: xorg 1:7.7+12ubuntu1 PackageArchitecture: amd64 Tags: xenial Uname: Linux 4.4.0-040400rc5-lowlatency x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: _MarkForUpload: True To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1528843/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
