Grey renderer on fullscreen, but only the first time

Has anyone else come across this, I have a patch, which is doing a 2048x768 pre-render and then an output renderer which I have going fullscreen 10 seconds after the patch loads. The first time it goes fullscreen its grey, if I drop out and go fullscreen again, all is fine.
TTY isn’t showing anything amiss, any ideas as to why this is happening, there is obviously a work around by dropping out and going back to fullscreen, but it would be nice if it did this first time around!

Ahh!
After scratching my head for ages over this, and finally posting the question, I go back and fix it straight off! I had a disabled overview renderer going fullscreen, hence the greyness!
Sorry for wasting your database on such a useless thing!

cat :)