private void updateSessionData() {
   List<String> watchExpressions = new ArrayList<String>();
   final List<? extends WatchNode> children = myRootNode.getAllChildren();
   if (children != null) {
     for (WatchNode child : children) {
       watchExpressions.add(child.getExpression());
     }
   }
   mySessionData.setWatchExpressions(ArrayUtil.toStringArray(watchExpressions));
 }