[xmonad] doFullFloat keybinding?

[1126]

Hello List!

I have a WS devoted to reading PDFs and alike and in my manageHook config stands 
the following:

               , className =? "Evince" --> doFullFloat

This is, because I like my two xmobars (top and bottom) to disappear, when 
reading a paper such things. But: When evince is FullFloating I got problems 
when opening more than one instance of it, like a second paper. It just lets the 
first one disappear under the freshly opened one.

What I would like to have is a keybinding to switch FullFloating on and off. Is 
this possible and if so, how? (By the way: another solution - maybe even a 
better one - would be to tell xmonad that if I hit F11 (go fullscreen) in evince, 
that this windows should be above the xmobars and should take the whole screen. 
Like VLC does.)

I couldn't find anything about it, I'm sorry for the noise if I just sucked at 
Google-ing ;) 

Thank you!