Extra lines being drawn

I’ve just started using MyPaint again after a4 year break. I like the enhancement, but I’ve noticed that when I draw using my Wacom tablet that it sometimes draws spurious brush lines on the canvas. This happens in two ways:

  1. I select a different brush from from a brush group window, and it draws a straight line from that brush’s icon to the the first point draw with my brush;
  2. iI finish drawing with a brush, and then start drawing again some distance away (on the screen).

It doen’t happen all the time, just often enough to be annoying. I’m using a Wacom Pen & Touch on a Windows7 x64 PC, Suggestions?

Question, do you happen to have the touchpad of the tablet on? I find that happens to me a few time when I use my tablet. Especially when I rest my wrist on it and pick up my pen just high enough where it start to take in touch input as well.

So far as I know, NO.