Making the window full screen on macos hides the dock and menu bar.
I find that when I make a video in Firefox 66 go full-screen that the menu bar and dock in MacOS 10.14.4 become hidden. I have looked at https://support.mozilla.org/en-US/kb/restore-menu-bar-firefox which confirms this behavior, but I am wondering how I can turn this feature off completely? This behavior does not occur with Safari or Chrome and it was a bit jarring the first time it happened to me.
In the below image, a Firefox window is full-screen on a second monitor.
Wšě wotmołwy (1)
Hmm, full screen should take over the entire screen, but only on the same display. I think you're saying that you have two displays, and when you go full screen on one display, it also affects the other display where you expect to still be able to use the menu and dock. That is very strange and I can't recall seeing it mentioned before.
I don't know whether this is a common issue with your version of MacOS or could be related to specific graphics hardware/driver software or settings. Hopefully other Mac users will have feedback on that.