[vtkusers] how to change the color of single picked cell

[Tracy]

Hi Everyone,

My application is to display a 3D model with a group of PolyData cells.
This model is represented by an actor. "vtkCellPicker" is used to select a
specific cell . My question is how to change the colour of the single 
selected
cell without any influence to the rest when the cursor is over this cell.

Any suggestion?

Thanks in advance.

Regards
Tracy