Part of taskbar getting overwritten

Hi, this is my first post here so apologies if this issue has been dealt with elsewhere.
I have a problem whereby the top edge of the taskbar gets overwritten by some applications. In the attached image this has been caused by the bookmarks pop-up in Firefox but similar things happen with other apps. It seems as if this area of the taskbar is not properly delineated so, although it is not possible to drag open windows over it, applications seem to be able to overwrite it
This is on a new-build system with Windows 7 and the various apps newly-installed and whilst not a serious issue any insights would be gratefully received.

Thanks for the reply. I can indeed do all that, and as I explained a window so treated does not cause any problems, even if it is moved so that it's bottom edge goes behind the taskbar.

The problem is that some applications (Firefox in the example I provided) can open a pop-up window which extends below the main app window and this seems to corrupt the top edge of the taskbar. Once that's happened it persists until (1) I hover over the taskbar icons in the affected area until the pop-up information text appears, which overwrites the corruption, or (2) unlock the taskbar and briefly drag it's top edge upwards and back.

Try changing the resolution on your screen.

Hi PhantomTa2,

I was using Windows Classic theme. Since switching back to Windows 7 Aero the problem has gone away. So it might be worth trying another theme.

Interesting - so it looks like Classic has a bug. I don't suppose there's a snowflake's chance in hell of Micro$oft doing anything about that.