I experimented with this for a while. It is difficult to get working and nearly impossible to get working every time. In other words, when you stick your finger to slide things, you never know if it is going to work or not, pretty much as if you were pressing a button without jitter removal.
You may want to change the way you register a click and introduce a "jitter protection" of a sort. For example, you may want to register a click only if there is no movement 500ms past the UP event.
PS: BTW, I have never been able to invoke Nokia's on-screen finger keyboard. I am always getting a stylus keyboard, even when touching screen with a finger. This may somehow be related to Canola problem described above.