> Hmmm, at least with Plasma 5.20 I can't reproduce this problem here. I can reproduce it very easily every time working on a directory full of PDF files.
Select a PDF file in Dolphin Erase the PDF (not moving to trash can) Automatically a new "thumbnail.so [kdeinit5] thumbnail" process appears in state S (interruptible sleep (waiting for an event to complete) according to ps) and a new "Qt Selection Owner for thumbnail.so" entry in xrestop. When these entries reach 256, X stops to open new windows. I'm running a killall -9 thumbnail.so every 5 minutes but this far from optimal
