I've got UserControl classes which contain UserControl classes which contain UserControl classes. I can set focus within each visible control without much problem. I only call SetFocus in a small number of scenarios, so I may not have discovered what you may be seeing. If you post an example of your problem you are more likely to get a quality response from the folks at SyncFusion.
Dade Behring, Inc.
(not a SyncFusion rep.)