Windows taskbar


Does anyone know why my taskbar on windows xp keeps changing size. I have it locked, but after it sits idle for a while (the monitor goes into a power save mode) the taskbar is either taller or shorter. I have to unlock it, click & drag it back to where it was & lock it again. I know this is a minor issue, but it's getting annoying. If I have jobs minimized in Flexi, they are hidden or way up on the screen. Is there a setting somewhere that needs to be changed or do I need to set it where the monitor won't go into power save mode?
Thanks in advance!