scroll m/wheel

Every now and then I lose the ability to click the wheel and auto scroll page? Any idea's why or how I can make a gesture for this.

Thanks

Either use pageup or page down to go a full page up/down. or
Use up or down to go up like youre clicking just the arrows on the side bar.
you could costomize it to do 3 up's for instance to go 3 clicks up for each stroke.
This is just an idea, I didnt test it. If you get this and do test it, leave a note if it worked or not.