Hi Charles Bates,
This behavior is expected since switching between tabs makes the TabControl unload the content of the last active item and load the content of the newly selected item, when the control is data bound to some collection of items. This load/unload operations involve add/remove actions in the visual tree, thus the content does not keep its state.
However, there is a corresponding item in our PITS,
which you can vote for thus increasing its priority.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items