F11 is the key Rated 5 out of 5 stars
Kept trying to find a way to activate the extension and then found in a comment/review about the F11. May have missed this tip, even on the web site.
Would be most helpful to old eyes and my lazy self if there was a add on to the drop down allowing activation using the mouse instead of the keyboard. A number of financial sites dont require keyboard usage. The thunderbird extension that shows full page gives this facility.
Just activated FullerScreen and it would be helpful if the mouse over the top of the screen could also show a top with Menu (as in Tiny Menu) and the so helpful Increase, Decrease, Normal provided in Text Size toolbar. Again old eyes.
Thank you for this extension.