* TreeNodeCollection.cs: Dont't recalculate the visible order on

    * TreeNodeCollection.cs: Dont't recalculate the visible order on
        inserted nodes that aren't visible.  This changes the
        max_visible_order which confuses scrollbar settings.
        - Use the enumerator to get the prev node instead of duplicating
        code.
        * TreeView.cs: Use new method for setting scrollbar values
        - Don't set the bounds every time the scrollbar is updated
        - When updating below the root node use an invalidate instead of
          a
        refresh to prevent the child controls (scrollbars) from being
        refreshed. (UpdateBelow still needs to be reworked anyways).

svn path=/trunk/mcs/; revision=61085