When viewing full-screen videos in Firefox 48.0.2, the address, tab and menu bars are still there. This happened after the last refresh. I would like to find a way to make them go away. Every question about this I find suggests right-clicking and ticking "Hide menu" ( which isn't there) or setting browser.fullscreen.autohide in the configuration to "true" (it already is). What might the problem be here, and how can it be fixed?