[sugar] commanding the movement of things on the screen

[Mikus Grinbergs]

This might have a bearing on the "jumpy cursor".

I use an external USB trackball, and do most of my work in Terminal. 
On numerous occasions, when I have moved the cursor to a scrollbar 
location above the slider, and have left-button clicked ONCE (to 
scroll up one screen's worth) -- the XO has spontaneously scrolled 
up many many screen's worth.

The best explanation I can come up with is that instead of 
"interpreting" a _single_ button-click command, the XO behaved as 
though a whole _series_ of such commands had been presented.
[I have no reason to believe that the trackball is at fault.]

If this guess of mine were correct, that might explain "overshoot" 
of a cursor movement - instead of acting on a _single_ cursor 
movement as input by the user, the XO might behave as though it was 
presented with a whole _series_ of movement inputs.


mikus