POINTER_MOTION_HINT_MASK causing problems with graphics tablet

[Nicholas Bishop <nicholasbishop gmail com>]

I have a custom drawing widget that receives mouse movements by
overloading on_motion_notify_event. Drawing can be quite slow, so I
use Gdk::POINTER_MOTION_HINT_MASK with get_pointer to get mouse events
as needed. This works fine, until I attempt to use a graphics tablet.
The graphics tablet only seems to work if I don't use
POINTER_MOTION_HINT_MASK.

I don't know how I could reliably switch between these two when the
user switches from mouse to tablet, and even if I could, it doesn't
seem like a good solution.

The full code for class Editor is here:
http://cvs.sourceforge.net/viewcvs.py/sharp3d/sharpconstruct/src/Editor.cc?view=markup