Silverlight 5 - Retain expanded/selected state in hierarchy

[Bylar]

Hello All,

In custom hierarchical radGridView control -
 1) Is there a possibility to retain expanded/selected state in hierarchy on rebind?
 2) Any possibility to expand only one child grid at one time ?
     eg In custom hierarchical radGridView control I have opened child grid for fist row now if i'll click on expand button on second row then my first row(child element) will collapse automatically. Is it possible ? How ?


 Please provide some help regard these two quires.



Thanks a lot
Anderson