Note: This only applies to using MEF Preview 8 on Silverlight, it does not apply to MEF in Silverlight 4
Yes I know we never did a Preview 8 post but……
We found a bug in PartInitializer (thanks to Kathleen Dollard for finding it!) in Preview 8 which affects MEF in Silverlight. The bug resulted in the default container that PI creates not being populated with any assemblies from the current XAP, which meant your imports would not get satisfied. This affected our Extensible Grid sample in that when you launched it you would not see any grid extensions.
The bug has now been fixed and we refreshed the release on 11/11.
Please download the latest bits to get the fix if you downloaded Preview 8 before the 11th.