Windows 7: strange "residue" on taskbar

I'm using Windows 7 Ultimate x64 with classic theme and NVidia 450GTS with latest drivers.
I have this strange behaviour with taskbar. For example:

pic.1 - everything looks good
pic.2 - expand firefox bookmarks which cover taskbar area
pic.3 - a little remnant remains on taskbar

anybody meets that problem? is this a graphic driver? I have no idea. there is a quite fresh system installation, about two weeks ago.

that happens also in "Win 7 Basic" theme but not i Aero. When Aero is ON everything is good. But I don't want Aero.

Welcome to the forum.

1. Click on the firefox tab
2. Click on Options Options
3. Go to the Advanced tab
4. Unselect Use hardware accelerations when available
5. Restart firefox. See if the problem goes.

Keep us posted.

Big thanks for that clue!
After disabling hardware acceleration in FF everything seems good

Thanks again!

Good to know!

You can mark the thread as solved

Why do you not want Aero?

Because i'm "old school" user ;-) Just an old habit, I also used classic theme on XP at work and at home (before Windows 7)

Seems quite a waste, your graphics card has all this power that Aero takes advantage of...but you rather put the burden of UI on your CPU...rethinking your old habit would be of benefit. With Aero almost the whole UI resides on the GPU and in video memory. Without Aero, the UI is handled by the CPU.

I have had that "residue" with FF and Classic Theme as well. Gonna have to see if online video plays properly with acceleration disabled.
UPDATE: Okay, no, video does not play back properly with FF acceleration switched off. Loss of audio sync. I'll live with the residue until I relaunch FF.

Just checked YouTube video with and without acceleration in FF. On my system there is no differences. I played 1080p clip and is EXACTLY the same cpu load. But there's a strange thing that cpu load is smaller on full screen than normal play in YouTube window. On full screen 1080p clip is play under 5% cpu load (typically 3-5%) and in window (no matter smaller or bigger window) cpu load is 8-10% - so I leave acceleration off.

Honestly I think you are being ridiculous to even sweat this.
Your system specs are very close to mine.
I don't understand why you are jumping through hoops for this. I really don't.
I run full aero and can still play any game title on the market maxed without trouble.
About the only thing I don't use is wallpaper. I think it's useless. I just set the background to black.