I've noticed, since the upgrade to Plasma 5.18.1 and subsequently also 5.18.2, that the mouse double click interval for desktop icons appears to be a shorter multiple of what is set for other locations, such as inside Dolphin (and other apps). I took the step to change from libinput to evdev in order to get the Advanced mouse settings back and manually change the double click interval. This had the effect of changing both Desktop and Dolphin, albeit still both responding to different intervals. Now I can actually double click an icon on the desktop reliably, but it is now much too sensitive in Dolphin.

Is there a specific setting which controls double click interval on the Desktop? It's almost like it is using Advanced Mouse Setting Interval * 0.5 or thereabouts.

KDE Neon 5.18
KDE Plasma 5.18.2

I did not notice this problem in Plasma 5.18

This issue seemed to be resolved for several months, but after an update a week or two ago, it is back. I am now on KDE neon 5.20, with Plasma version 5.20.5. Rebooting seems to randomly resolve the problem for a random period of time before it reverts back to whatever is causing it. Any help would be greatly appreciated.