ADT's Project Navigator performing slowly

When you dragged a view into a sheet with Project Navigator, it took several seconds or longer for the view to be inserted.

For tips to improve performance in this case as well as with other issues in ADT 2005, ADT 2006 and ADT 2007 look at this KB article: Project Navigator performing slowly. There are 17 guidelines to follow. Some of them apply ty ACA 2008 as well I would say.