Comment # 20 on bug 1045798 from Stefan Hundhammer

The screenshots tarball contains other permutations of the same scenario:
Running from the root shell with different widget themes, running as a regular
user with different widget themes, running as a regular user, but with "kdesu"
with different widget themes.

There must be some Qt5 or KDE lib or plug-in that makes it behave differently.

I also checked on my workstation with yesterday's Tumbleweed, and it works fine
there (all buttons using Alt-H, no shortcuts reassigned), but I am using Xfce
there, not KDE. But the Qt libs are also the most recent Qt 5.9 versions.