Comment 8 for bug 1801161

Oliver: there's a bug for pcmanfm (https://bugs.launchpad.net/ubuntu/+source/pcmanfm/+bug/1782984) with the same end result. This seems to somehow related to GTK2, as there are several other applications that show the same behavior (https://bugs.launchpad.net/ubuntu/+source/gtk+2.0/+bug/1808710). There's a file manager called SpaceFM one user tried and it showed the problems with the GTK2 version but not with the GTK3 version. This, coupled with Ilya's suggestion, leads me to believe GTK2 is indeed the result. With pcmanfm, though there are specific behaviors that cause the bug, it's not 100% reproducible. Sometimes those behaviors cause the error and sometimes they do not.

However, Gérald's comment comes as something of a shock.