This behavior is caused by the fact that when you select a RadTreeViewItem
on MouseClick the item is selected and focused at the same time. However, selecting an item in code behind only selects it and doesn't focus it unless you implicitely focus it as well.
So I'd suggest you look into the Focused
visual state of the RadTreeViewItem
and the style changes it applies. I hope this info helps. Still, if it doesn't, you can send us a sample project reproducing the issue and a snapshot illustrating your goal and we will help you implement it.
All the best,
the Telerik team
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