Version:           unspecified (using KDE 4.6.1) 
OS:                Linux

I have seen this problem on three computers now: some crash occurs, and then you can't turn kwin compositing on, the "all effects list" is empty, and you don't know what to do.

In the past, I solved it by deleting kwinrc and letting kwin create it again.

Today I decided to investigate and found out that the "OpenGLIsUnsafe" flag being true is what causes this, and that setting it back to false fixes this.

But I think the way this is currently handled is a bug! How can a normal user discover this? Most users get stuck and can't figure out how to reset kwin, or what's going on. Additionally, even if you switch to Xrender compositing, the "All Effects" list of plugin sstays empty.

I think the configuration dialog should tell the user what is going on and offer the option to undo this, otherwise most non-advanced users won't be able to ever solve this (there are a million other reasons for kwin to fail, so they will probably never find the answer on google without knowing how to search).

I know that if opengl is truly unsafe, then the user should be really warned about trying to enable compositing, but what if the user updated their driver and the source of the original crash is gone?

Finally, I know that this isn't kwin's fault (something crashed in the first place), and fortunately on my desktop this never happened, but I still think this should be handled better, so users know what's going on.

Reproducible: Always