Yeah, the problem still exists for me also.
The solution is don't use Heigharchial Menus, haha. Then only an admin will run into the problem when he hovers over the admin menu. Hopefully it is resolved in a future release, it's been around even in DNN 2. Maybe The CSS Only Menu will not suffer from this instability.
Don't take my post wrong, I like the solpart menu and commend it's designer for the flexibility and configuarbility(Is that a word). But for the webmaster of a large public site, it is not acceptable to put a product with these issues into production.
I'd also like to vent about the Remeber Me Feature of the login control, but I'll save that for another thread.