KDE (or X?) clipboard goes stupid

[Jerome Yuzyk]

On Saturday, December 9, 2017 12:47:46 PM MDT Jerome Yuzyk wrote:
> [kf5 5.38, plasma-workspace-5.10.5, Fedora 25]
> 
> My KDE/X clipboard goes astray sometimes. I Copy URL to clipboard from
> KMail, for example, and when I paste I get something from a day ago pasted.
> 
> Is there any way to reset that clipboard without restarting X or KDE? I'm
> not talking about Klipper, but the default clipboard.


[Now on kf5 5.54, plasma-workspace 5.13, Fedora 28]

Klipper is disabled.

Both X and KDE clipboards are messed again, after 57 days of uptime. Ctrl-X 
will cut, but Ctrl-V pastes whatever was left by the last non-KDE Ctrl-V (like 
from Chrome). The X clipboard is not filled by highlighting either. This 
happens to the main KDE apps I use: KMail, Konqueror, Konsole, and KAlarm. It 
does not happen to non-KDE apps like SeaMonkey or Chrome. It's damned annoying 
and ongoing for years.

Does anyone have any idea how to "reset" KDE's clipboard management without 
logging in/out?