If you're having trouble with applications fitting on the screen (for example, you can't see the "OK" and "Cancel" buttons) then a useful trick is to hold the ALT key and then click-drag the window around until you can see it again.
As for the actual setting of resolutions - the KDE applet will only allow you to change to resolutions already defined in your XFree86/Xorg configuration files. You should check out the file [i]/etc/X11/XF86Config[/b] and look for a bit that looks like this:
Code:
Subsection "Display"
Depth 8
Modes "1600x1200" "1400x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
EndSubsection
Obviously you won't have all those resolutions in your config file. Just a note, the order is only important in that (in this example) it'll start out with 1600x1200 and if it can't use that, it'll drop to 1400x1050, and so on. Also, pressing <CTRL><ALT><Numpad +> will drop resolutions in the same order.
You will need to be root to edit the file. Once edited, you can re-start the X session by pressing <CTRL><ALT><Backspace>.
Hope this helps.
