Drawing free-form lines via the mouse

I'm currently using a picturebox control to display a bitmap on which I'm
drawing free-form lines that the user creates with the mouse. Currently,
this is done in the MouseMove event of the picturebox control, looking for
the left button. Right now, the drawing is very intermittent, meaning that
if I move the mouse faster than a snail's pace, it doesn't draw
consistently - it leaves gaps. Almost as if the mousemove is too fast for
the event handler to catch. Right now, I'm ONLY using the emulator and the
mouse as I don't have a physical Pocket PC. Is this more an issue with the
emulator or will it appear on the real device as well when I try to draw
free-form lines via the stylus? Is there a better - faster - way to capture
the mouse (stylus) movements and draw a line where the mouse is moving?

Thanks,
AKM