pages documents will not go full screen
2009 Macbook 2.26 ghz, intel core 2 duo, running OS X Yosemite 10.10.1. Most recent update of Pages has left me without the ability to go full screen on my documents. (Teacher who projects quizzes in fullscreen - problematic without this ability). When I click full screen is goes there for one second or two then automatically backs out. If I go under the view tab I cannot select "full screen" although visible, it is shaded as if it is not an option.
I have checked for updates, I have restarted my computer.
Please advise.
MacBook, OS X Yosemite (10.10.1)