Dont worry if you are using compiz and the title bar of all your windows suddenly disappear…this is just because the window decorator you are using has crashed….
Now there are two ways to get out of it…clean one is restart you machine….but if u r stuck with something and dont want to restart then just use the following command —>
1. “kde-window-decorator –replace” (if you are using the kde3 window decorator).
2.”emerald –replace” (if you are using emerald window decorator).
3.”kde4-window-decorator –replace” (if you are using kde4 window decorator).
And if compiz-fusion as a whole crashes the try the command “compiz ccp&”.
But u will need a restart eventually to make EVERY thing normal.

