Diễn đàn hỗ trợ Firefox

I've tried going into Full Screen mode three different ways:

• Clicking the green MacOS button in the upper left of the window
• In the Firefox menu in the upper right, to the right of the Zoom choice I click the full screen icon
• Pressing Command+Shift+F

But whatever way I do it, I still see the tab bar, address bar, and bookmarks toolbar rather than a true full screen. Not sure what I'm doing wrong.

I'm using the OneTab add-on, Enabled. The icon no longer shows on the Toolbar, though it is on the Menu bar next to Firefox View.

I ran Remove and then Added it again, hoping the Toolbar Icon would reappear = no go, And I lost all URLs already saved, stupid me. To be clear, clicking the Icon on the Toolbar saves all open tabs.

Is there a fix via Preferences? Thanks. gw