If I use a GridView without TabControl, it is displayed fine:
However, if I put it in a RadTabItem of a RadTabControl, not all horizontal gridlines are visible.
If I set ShowGroupPanel of the grid to True, all gridlines are visible!
Is there a drawing problem in the RadTabControl?
Edit: if i try a regular .NET TabControl, it has the same issue! So maybe it's a GridView issue...
Edit 2: if I set ShowColumnHeaders to False, all lines are visible