Every once in a while, at random, I can simply mouse over my taskbar, and my windows will rapidly switch between themselves. If I have just one open, it will minimize and maximize at insane speed. Any menus I click anywhere disappear immediately. Sometimes the glitch will correct itself, and sometimes I have to hit reset. I'm using Arch Linux and KDE 4. I haven't been able to find any mention of this anywhere. Is it a mouse driver issue or what? I really like KDE, and I don't want to have to uninstall it.

Do you use xorg.conf? If so, check if you configured ZAxisMapping properly, if your mouse has one scroll, this entry should have two buttons defined. You haven't gave much details, so it's just a guess.

Sorry, I'm kind of a newbie. No, I don't use xorg.conf.

create a new user and see if it has the same problem

What kind of mouse do you have? Can you reproduce this in other applications, i.e., unintentional scrolling?

Sounds as though the mouse is dirty or sticking somewhere or does this _only_ occur with KDE?

Another possible cause could be the video driver not playing nicely with some effects or plasmoids (you have fancy tasks?).

I've seen something that sounds just like this on my netbook (an Asus 1215T) under KDE 4.6 with the device's trackpad.

For me, rebooting fixes it, so I'm guessing it's a software issue, not a hardware issue, and I've never seen it happen under Win7 on the same machine. I wouldn't guess it's KDE specific though - feels more like some driver problem? I haven't tried other desktop environments though so I'm not sure.

"Sometimes the glitch will correct itself, and sometimes I have to hit reset"

BTW, it behaves exactly like that for me, too. But I haven't seen it on my desktop machines - only on the netbook.

No, my mouse isn't dirty, and yes, it only occurs with KDE. Creating a new user didn't do anything.

So what other DEs/WMs have you tried? You don't happen to have a mobile or cordless phone on your desk, in the vicinity of the receiver of your cordless mouse???

I'm fishing here because we haven't got anything to go on. I bet you've found the mouse settings in systemsettings but they are not really useful in this case I suppose. If none of the above is applicable I'd disable all desktop effects and see whether the behaviour persists...

I've used several other distros on this computer, including Ubuntu, Vector, and Mint, but I like Arch the best. I've used GNOME, and didn't have (major) issues, though I found it lacking.
I don't own a cellphone at all. They irritate me. And I don't have a cordless phone either.
Unfortunately, the mouse settings didn't help. I disabled the scrollwheel in the system settings, but it didn't affect the scrollwheel in the taskbar.
The glitch is very intermittent. I can go hours or days without it happening. Usually, when it happens, if I keep the mouse away from the taskbar, it'll settle down in about half an hour.

Cheers. Going on that I'd say it is kwin.

If none of the above is applicable I'd disable all desktop effects and see whether the behaviour persists...

Try disabling any mouse related effects first. Trial and error I'm afraid.

Alternative approach: You sure you have the right video driver? Then again, if Gnome worked fine you may well have.

The glitch hit again, and I disabled all the desktop effects and rebooted. The glitch started instantly this time, and much worse. The windows switch even faster. It seems to have spread to other windows and menus as well. Firefox seems immune, but if I click on the applications menu it disappears immediately, and Pidgin, which uses tabs to switch between message windows, cycles through them wildly.

Is this USB mouse? What happens when you reconnect it?
Do any strange messages appear in dmesg or Xorg.log?

The glitch is very intermittent. I can go hours or days without it happening. Usually, when it happens, if I keep the mouse away from the taskbar, it'll settle down in about half an hour.

That's exactly what I see too, for what little that's worth . It's often OK for days, and I have no idea what prompts it to happen. Also, when it happens, it seems to get progressively worse as I use the system; it'll start off happening a little bit, and become unusable if I try to "press on" without rebooting.

I don't see it with my USB mouse, although that has other issues (needing to restart X.org if it loses contact with the mouse for a few moments, which is annoying).