Something strange has happened to my KWin effects tab.
On the "Desktop Effects->General" tab, the "Enable desktop effects"
item is ticked, but grayed out. The "Composting State" has a green tick
and says "Desktop effects are active".
If I click onto the "All Effects" tab, its contents are blank!
But, interestingly enough, as indicated by the green tick, my desktop
effects do run fine. Window Transparency, Gray Parent Window when
Child Dialog active, etc.
Also, going to the "Advanced" tab, I can only select the XRender compositing
type. Any attempt to select OpenGL causes a error dialog to appear saying
that compositing could not be enabled, and it reverts back to XRender.
The "All Effects" tab used to have a long list of KWin effects, after all I previously
turned on Window Transparency, etc. Now I cannot alter my effects configuration!!
Any thoughts are welcome.