Solved Firefox Menu Toolbar Issue

I recently had a Firefox update, which decided (without any input from myself) that I really could do with an increased sized toolbar (the one that runs along the top of the screen). It now occupies nigh-on a full quarter of the screen space (!) on my Asus notebook (11" screen) and there seems to be nothing I can do to restore the toolbar to its original size. I have sought aid online, but as so often is the case, the solutions they offer refer to menu options in Settings that my version doesn't possess. I've also tried using the Ctrl and '-' keystrokes, but that has zilch effect on the toolbar itself.

With our local PC repairs shop having ceased trading means I now have nowhere else left to turn.

Hi, Bruce. Yes, I mean the main Firefox menu bar, not just the bookmarks bar - though that too exhibits the same problem. I'm afraid I don't have the necesssary expertise to trust myself to uninstall Firefox, then reinstall it again safely. More hand-holding is needed here, sorry to relate.

A friend managed to partially resize the toolbar. Not entirely sure how he managed it as yet (possibly he doesn't either). It's not perfect, but a lot better than previously. One theory for the cause centres on the fact that I had earlier increased the size of the laptop's Win 10 OP's fonts (more particularly those on MS Office 2007's toolbars). These were initially so weenie that there were times when I had to use a magnifying glass to discern the script at all. Consider it: 16th century optical technology brought in to compensate for a 21st century technological shortfall. Quite remarkable. At any rate it appears that this font enlargement of mine may have had a causal knock-on effect upon Firefox's own increase in the size of its toolbar. It's just a theory, of course. But here's the thing: after the WIN 10/Office 2007 fonts fiasco was (properly) cleared up, Firefox likewise followed suit. . . well, it went a good part of the way at least. So that's the situation at present. I remain bemused and confused, but at least I've now got more of my screen back as far as being online is concerned. Thankfully too the magnifying glass is back in its slipcase. All in all I'd call that a partial win-win.

Thanks again for your help, and please excuse my rambling responses.