Just got a rare taskbar error (and not reproduceable), but it may be of interest. Previously working in a few programs (Cinema 4D, Warcraft (NOT fullscreen), FireFox). Warcraft was no longer running.

Opened up DF to find new images on Flickr. Clicked on "Get Settings" and then went back to FireFox that was minimized on the second monitor. The taskbar went wacky. (pic attached). Had to quick DF and restart it. Can't reproduce and probably won't happen again, but it may be of some interest...

Just had it happen again. Had Cinema 4D open (for what that's worth) and camstudio. Had just gone to DF's settings to check wallpapers from (in this case) flickr. (see attached)

I'll probe into this further and see if I can narrow things down a bit.

Ben, also checking system resource usage when this happens will be a good idea - such as high CPU usage, low free RAM, etc...

Both machines have 4 gigs ram and very low ram/resource usage (I check often). One is a high-end Intel Dell workstation (NVIDIA) and the the other is a high-end AMD home built (ATI).

hmmm - then I wonder if it is an app that is interfering with the polling of the taskbar, which causes it to go stupid when it cannot get an answer from the polling?

Could it be perhaps a longer than normal UAC access request, such as one that doesn't get answered right away, or else one that has multiple UAC requests, or even an app that loads multiple children, all with elevated privileges because of inheritance?

I believe User Account Control (UAC) was introduced in Vista. I'm running XP on both my machines.

Edit: came into work today and the DF taskbar was showing incorrect/updated buttons again. I only had Notepad++ on the second monitor, but DF was showing an old explorer button/icon with the Notepad++ text. Next I fired up winamp and it also showed the Notepad++ button text. (see attached)

Are your power settings allowing the HD to turn off after inactivity?

At work, I believe so. At home, no...