No, unfortunately there is no way to load the visual tree for content that is not currently selected.
As far as I know the Toolkit TabControl behaves similarly.
This is done for performance reasons mainly since loading controls that are not visible is unnecessary.
My suggestion is to databind the control that you want to change. This way you can change its status whenever you need by changing the property it is bound to and it will be updated when the user switches to its tab.
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