You can re-style the SeriesItemLabel control as shown in this example. Moreover, you can wrap the border element around a LayoutTransformControl. Attached is a working example.
Hope this will help.
Best wishes,
Velin
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?
Explore the
Telerik Public Issue Tracking
system and vote to affect the priority of the items.