How to lock the cell placement

Hi, 

can someone help in locking the placement of the Instance (should not be able to move the instance once i lock the position) in the virtuoso layout editor using skill..

It is equvivalent to this command SET_OBJECT_FIXED_EDIT(GET_SELECTION) 1 (1 means postion fixed, 0 means postion is notfixed).This command is available in the IC compiler (ICC tool). 

Thanks for your support,

Bharath.