When logging in, edges are sometimes unresponsive, ie right click on the edge brings the usual right click menu instead of the Compiz command. And yes, compiz is running (wmctrl -m -> Compiz).

It can be fixed with a "compiz --replace" but it's a bit frustrating. 

Any idea how to fix this ? or to check Compiz logs on startup ? Known bug ?

Also, unrelated, Compiz scale plugin "on a group of window" NEVER works...