[c#]
//code in flygrid initialization
this.dataGrid.NodeFocusChanging += new NodeBoolHandler(dataGrid_NodeFocusChanging);
//define index of column with locking
private int lockedColumnIndex = 1;

private bool dataGrid_NodeFocusChanging(object sender, NodeBase node)
{
  object objLocked = node.GetValue(lockedColumnIndex);
  //if objLocked == true we return false and disable selection of this node
  return objLocked != null ? !((bool)objLocked) : true;
}