TouchScreen scrolling?

[captain deadly gmail com]

Hello all,
    trying to write an app that runs on a touch screen device without a mouse. 
I can't find too much info but could well be looking in the wrong place or with 
the wrong search string.

I've a list of items in a TreeView which I'd like to be able to grab to 
scroll. At present I'm presenting a popup menu on a double click so that I 
don't confuse the click to drag with the double click. Is there some way of 
achieving this grab to scroll functionality in gtk?