Some time ago I was able to run a *.desktop file by double clicking it in dolphin. Right now if I do this it only opens it's definition in Kate.
This might have started with this update [Stable Update] 2019-02-09 - Kernels, Deepin, Firefox, Wine, Python, Haskell but I'm unsure, since I don't use this feature very often.
Or is it some configuration problem I inadvertently caused myself?
my system details: Dump your "inxi -Fxxxza --no-host" here and bookmark it