diff --git a/lib/galaxy/webapps/galaxy/controllers/root.py b/lib/galaxy/webapps/galaxy/controllers/root.py
index 704f62e295a..3a4ac83bc45 100644
--- a/lib/galaxy/webapps/galaxy/controllers/root.py
+++ b/lib/galaxy/webapps/galaxy/controllers/root.py
@@ -172,12 +172,16 @@ class RootController( BaseUIController, UsesHistoryMixin, UsesHistoryDatasetAsso
 
     ## ---- Dataset display / editing ----------------------------------------
     @web.expose
-    def display( self, trans, id=None, hid=None, tofile=None, toext=".txt", **kwd ):
+    def display( self, trans, id=None, hid=None, tofile=None, toext=".txt", encoded_id=None, **kwd ):
         """Returns data directly into the browser.
 
         Sets the mime-type according to the extension.
+
+        Used by the twill tool test driver - used anywhere else? Would like to drop hid
+        argument and path if unneeded now. Likewise, would like to drop encoded_id=XXX
+        and use assume id is encoded (likely id wouldn't be coming in encoded if this
+        is used anywhere else though.)
         """
-        #TODO: unused?
         #TODO: unencoded id
         if hid is not None:
             try:
@@ -192,6 +196,8 @@ class RootController( BaseUIController, UsesHistoryMixin, UsesHistoryDatasetAsso
             else:
                 raise Exception( "No dataset with hid '%d'" % hid )
         else:
+            if encoded_id and not id:
+                id = trans.security.decode_id( encoded_id )
             try:
                 data = trans.sa_session.query( self.app.model.HistoryDatasetAssociation ).get( id )
             except:
diff --git a/test/base/twilltestcase.py b/test/base/twilltestcase.py
index fc76281e97f..dad6deaafaf 100644
--- a/test/base/twilltestcase.py
+++ b/test/base/twilltestcase.py
@@ -826,8 +826,10 @@ class TwillTestCase( unittest.TestCase ):
                 if ext != test_ext:
                     raise AssertionError( errmsg )
         else:
+            hda_id = self.security.encode_id( elem.get( 'id' ) )
             self.home()
-            self.visit_page( "display?hid=" + hid )
+            # See not in controllers/root.py about encoded_id.
+            self.visit_page( "display?encoded_id=%s" % hda_id )
             data = self.last_page()
             if attributes is not None and attributes.get( "assert_list", None ) is not None:
                 try:
@@ -918,7 +920,7 @@ class TwillTestCase( unittest.TestCase ):
         if base_name is None:
             base_name = os.path.split(file_name)[-1]
         temp_name = self.makeTfname(fname=base_name)
-        self.visit_url( "%s/datasets/%s/display/%s" % ( self.url, self.security.encode_id( hda_id ), base_name ) )
+        self.visit_url( "%s/datasets/%s/display/%s" % ( self.url, hda_id, base_name ) )
         data = self.last_page()
         file( temp_name, 'wb' ).write( data )
         if self.keepOutdir > '':