Comment # 21 on bug 974627 from Stefan Hundhammer

This might be just the combination of that Qt version (5.6) and that window
manager (icewm). Maybe it's special in the inst-sys where we use the
framebuffer X server (AFAIK); maybe it doesn't have an X extension that is now
in heavier use than before.

But that's a lot of maybes. From what I can see, the only meaningful change was
the Qt update from 5.5 to 5.6. Since the Trolls don't change that much any more
in the Qt widgets area, IMHO it would be worthwhile to check if there were any
changes in any of the q*x11*.cpp files. And our own patches, of course.

I'll try to have a hard look at the Qt 5.6 vs. 5.5 sources with and without our
patches.

Coming up with a useful test case might be a challenge; preferably one that
does not force us to rebuild the installation ISO (build RPM, make DUD,
integrate DUD into ISO etc.). But maybe we have to do just that, even though
it's painful.