Firefox covering taskbar when maximised

Firefox covering taskbar when maximised

Just today, I have noticed that Firefox (updated to 23 for about a week),
when maximised, is covering the Windows taskbar, which is quite annoying.
After trying a few different applications, I can confirm that only Firefox
is doing this.
Is there any way to restore normal behaviour?
A couple of things I will point out in advance to avoid misunderstandings
that seem rife with the troubleshooting pages I have found so far:
Firefox is covering the Windows 7 taskbar, not any Firefox toolbars.
I am not in fullscreen mode.
The "Autohide the taskbar" setting in Windows is off.
Things I have tried already:
Rebooting.
Solution outlined in: Corrupt localstore.rdf.
Browsing through about.config for any obvious setting related to window
positioning, screen heights, and so on.
My last resort is to uninstall/reinstall Firefox.