"Even with the window maximized, it should never cover the status bar at the bottom of the Windows screen."

when I hit F11 in my either my Mozilla browser or Opera browser, it maximizes and DOES cover the entire screen, including the Windows taskbar...in Mozilla, it leaves me the 'X' to click to close it, and the +,- etc., but in Opera, there is NO title bar, no control icons, -,+ or X, no taskbar...nothing but the site window. If any other windows are open, alt-tab would likely get you back to the task bar, but I'm not sure what that would solve.

It may well be that the offending site somehow initiates whatever each browser can do regarding maximizing... I know if that just 'happened' in Opera, I might not think to try hitting F11 to recover....well, until now, that is..