Hello Tim Tos,
This is a known issue in the RadTreeView
control in this scenario. It is logged in our PITS
where you can track its progress and vote for it thus increasing its priority.
Unfortunately I am not aware of any workarounds at the moment. I hope this is not a showstopper for you.
All the best,
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