Kdesu is not working on any application. I tried it for Dolphin, SystemSettings5, Kate, etc.
On Dolphin when I Right-Click the Menu to run Dolphin as root it also never launches.
KDE Plasma Version: 5.14.2
KDE Frameworks Version: 5.51.0
Qt Version: 5.11.2
I'm afraid this is intentional. Running Dolphin as root was deemed too dangerous due to security vulnerabilities. We are implementing PolicyKit support so that you don't have to run Dolphin as root to edit files owned by another user. That's tracked by
*** This bug has been marked as a duplicate of bug 179678 ***
As for the other apps, kdesu is not supported and its use is discouraged. It's not surprising that it fails.
(In reply to Nate Graham from comment #2)
> As for the other apps, kdesu is not supported and its use is discouraged.
> It's not surprising that it fails.
PolicyKit for Dolphin will be an awesome alternative. Thank you.
Awesome? The PolicyKit KCM GUI is no longer there, so I cannot really concur at this moment.