My panel is set to "Windows can cover". I'd already noticed that it had a tendency to pop to the foreground without any evident reason (event) in my Kubuntu 14.04/KDE-4.13 install. Didn't seem like a big deal.
Now I'm running that install on battery power for the 1st time, and the panel pops to the front every 20 or 30s or so, even when I'm doing absolutely nothing. It seems that in absence of activity it'll stay there, while it'll pop back after a couple of seconds when I'm doing something, like typing this message.
From what I can see there are no applications/windows trying to get my attention, the notification centre has no notifications for me - in short, the only thing in the panel that might see regular updates is the battery monitor icon.

I'd never noticed anything like this in my main install, LMDE with KDE 4.11.3 - which I've used on battery extensively.

Any idea how to hunt down what's causing this?


EDIT: I went over the hidden icons in the SystemTray thingy; after quitting the 2 ktimetracker instances (?! I never even used the app this session) and deactivating the touchpad icon behaviour seems to be back to normal.

Thanks for posting the solution - rather interesting that KTimeTracker / Touchpad applet would cause that.