That particular bug was introduced in Windows Vista SP2 and Windows 7, and yes, it has been corrected in Dreamweaver CS5.
I know that there are bugs that where fixed, but there could be others I am not aware of that weren't.
The question of what was or wasn't fixed (by Adobe) in DW CS5 would be better directed at Adobe then here.
I can say that unlike CS4, Adobe has released 3 updates to CS5 so far since it's launch.