For ages I was plagued with FF opening twice. One click - opens in task manager only, 2nd click opens to desktop. Or maybe I'd go to use CCleaner and up pops a message 'need to close FF' - was still open in the background. Google + Mozilla forums never came up with the answer. A real PITA.
The other day I realised it didn't happen any more - 1 click, 1 FF. When did this amazing fix take place ? This should've been headline news in DS, El Reg, News at Ten, PM's questions etc.