Multi-touch [ Devel Digest, Vol 98, Issue 6]

[James Cameron]

Speculation: some of the tests fail because a tester is using gestures
that have worked on a conventional touchscreen.  The XO-4 has a tilted
XY infrared touchscreen, and so certain gestures become ambiguous when
the fingers cross on XY coordinates.

If so, and the functions can be discovered, then a naive learner will
rapidly figure out gestures which work reliably.  The learned gestures
will also work on a conventional touchscreen.

-- 
James Cameron
http://quozl.linux.org.au/