Is it possible to replicate the search functionality found in ListGrid and implement it for a TreeGrid to find all the tree nodes which matches the search criteria?
Here is the one for the ListGrid:
http://www.smartclient.com/smartgwt/showcase/#grid_adaptive_filter_featured_category
TreeGrid extends ListGrid. So whatever functionalities you're getting with ListGrid, are also available with TreeGrid. You can definitely have searching functionality in TreeGrid by these properties:
myTreeGrid.setShowFilterEditor(true);
myTreeGrid.setFilterOnKeypress(true);
But these functionalities will work only if you're using DataSource for generating the TreeGrid as per my knowledge.
Hope this information helps you.