I can also confirm that in Lucid Alpha 2 this bug is not an issue anymore for Dell Inspiron 5100 with Radeon Mobility 7500. Everything works well including notification pop-ups. The only problem that appeared again - flash works terribly slow in Firefox. It worked well in Jaunty, then it became too slow in Karmic, then somewhere in between Lucid Alpha 1 and Alpha 2 it worked normally. But now after several updates it works bad again.
I can also confirm that in Lucid Alpha 2 this bug is not an issue anymore for Dell Inspiron 5100 with Radeon Mobility 7500. Everything works well including notification pop-ups. The only problem that appeared again - flash works terribly slow in Firefox. It worked well in Jaunty, then it became too slow in Karmic, then somewhere in between Lucid Alpha 1 and Alpha 2 it worked normally. But now after several updates it works bad again.