+- optimize speed in hand tool (process groups of motion events)?
+ (setting 1 pixel min threshold doesn't help -- look at GTK+ scrollbar code?)
+- layer dialog box to set visibility status of each layer regardless of
+ which layer is being edited
+- display corruption on scroll down when bottom of window is obscured??
+ (probably a gnomecanvas or X bug -- expose event generated for wrong
+ region, or not processed?)
+- bitmap preview for document icon in desktop environments?