Someone said it did in another thread. I am not sure if it has any effect. Havn't had problems since installing it though.
This may be anecdotal, but I haven't had disappearing cursors since I've installed the .Net Framework 4 beta.
Updated to .NET Framework 4 RC, had disappearing cursor again. It never happened with Beta 2 for the week or so when I had it. Can anyone running Beta 2 confirm that it fixes the disappearing cursor issue?