No "Drag and Drop" from GTK to Plasma

[Lanzi]

For about a year now I have the problem, that if I pull a pic or a video from Geeqie into Krusader or kdenlive it doesn't work. I also cannot pull into firefox. The mouse shows a symbol similar to the traffic sign for not-parking allowd.
On my kubuntu-laptop it worked all the time, so I think something may be missing on my siduction.

Any ideas?

[Lanzi]

ANybody could confirm this?
Is there a special programm, that got uninstalled?