Version:           unspecified (using KDE 4.5.0) 
OS:                Linux

If you add a monitor configuration in Display Settings that moves the taskbar to another monitor with a higher resolution than your main screen, the panel think the width of the new screen is the same as the original one.

See steps to reproduce...

Reproducible: Always

Steps to Reproduce:
(In case it matters, I am on an HP G70 with an Intel GMA 9xx)
1. Plug fancy new monitor in (in this case it is a VGA screen)
2. Open Display Settings
3. Set second monitor to a higher resolution than your primary screen
4. Set second monitor to be to the right of your primary screen
5. When the panel moves to the second screen, it will only be as wide as it was on the primary screen.

Actual Results:  
When the panel moves to the second screen, it will only be as wide as it was on the primary screen. Hitting the cashew shows that the panel cannot see any additional width on the second monitor, either. However, you can sometimes "reset" what it thinks by moving it to a different screen edge and then back to the bottom. Once you do this and make it wider, though, the K-menu gets really wide, too.

Expected Results:  
The panel should adapt to the full width of the screen if that is what it was set at on the primary screen, or it should use up the same percentage of the new screen as it did the old one.

All of my settings are default KDE 4.5 settings (as default as Kubuntu is) except that I am using SmoothTasks instead of the standard task widget.