question: private void handleDoubleClick ( DoubleClickEvent e ) { ISelection selection = e . getSelection ( ) ; if ( selection instanceof IStructuredSelection ) { IStructuredSelection structured = ( IStructuredSelection ) selection ; if ( structured . size ( ) == 1 ) { Object first = structured . getFirstElement ( ) ; if ( first instanceof ISVNRemoteFile ) { openAction . selectionChanged ( null , selection ) ; openAction . run ( null ) ; } else { treeViewer . setExpandedState ( first , ! treeViewer . getExpandedState ( first ) ) ; } } } }
target:  The mouse has been double-clicked in the tree, perform appropriate behaviour.