Stop scrollwheel changing window

[risingup]

In both KDE and GNOME, when the mouse is over the Task Manager, scrolling changes the window focus.

Is there any way to disable this? I am configuring a computer for someone with a vision impairment and it is hugely confusing for him, especially as he sometimes doesn't realise he's moved the scroll-wheel.

Thanks.

[MfBdL7]

do you have ccsm installed if so go to system>preferance>advanced desktop effect settings. go to desktop and if the desktop wall plug in is checked, un check it and your gtg

also just right click the boxes> preferances and make the columns and rows 1