The display full screen is a very useful option but with the new changes coming to Firefox:sidebars and vertical tabs, the feature needs to be revamped. I propose that the new full-screen display feature should also hide the sidebars. I would also like to propose for us to be able to customise what is hidden when we are using the full-screen display feature, by default it should hide everything, but we can customise it. Something similar to the customise toolbar option. Perhaps we can even expand the customise toolbar option so that we can customise what is hidden when using the full-screen display feature in a separate page or something.