Silverlight .NET Controls V2.6 Released [February 4th, 2008]
This release fixes a problem with the tree view control and the slow response when populating large numbers of child nodes. This was due to each node having a fade-in animation which is started when the node is added to it's parent, and it would seem Silverlight cannot handle lots of animations happening at the same time.
The solution to this was to remove the effect, this has speeded up child node population considerably, there was also a problem with the responsiveness of the scrolling when large numbers of node were displayed and this was caused by the number of event handlers attached to the various node components. After a bit of optimization this has been solved and the scrolling is much smoother, even with large node lists.