Switch workspace with the wheel - a better way howto?

Hi,

I'am aware of the possibility to bind "next workspace" and "previous
workspace" to the wheel up (and down) buttons of the mouse. However this
does not work allways. If I use the wheel (when the mouse arrow is over
the root window) then I have to click on the root desktop first and then
use the wheel to really switch it.
I guess there is no "mouse arrow position check" like in fluxbox where one
can change the workspace with the wheel as long the arrow is over the
desktop? Or is it?

Thanks,

Stefan