Merged in jmchilton/galaxy-central-fork-1/stable (pull request #479)

[STABLE] More collection-y workflow fixes.

lib/galaxy/tools/parameters/basic.py

@@ -2107,6 +2107,8 @@ class DataCollectionToolParameter( BaseDataToolParameter ):
     def to_string( self, value, app ):
         if value is None or isinstance( value, basestring ):
             return value
+        elif isinstance( value, DummyDataset ):
+            return None
         try:
             if isinstance( value, galaxy.model.DatasetCollectionElement ):
                 return "dce:%s" % value.id

static/scripts/galaxy.workflow_editor.canvas.js

@@ -1711,7 +1711,14 @@ var BaseOutputTerminalView = TerminalView.extend( {
     },
 
     onDragEnd: function ( e, d ) {
-        d.proxy.terminal.connectors[0].destroy();
+        var connector = d.proxy.terminal.connectors[0];
+        // check_changes_in_active_form may change the state and cause a
+        // the connection to have already been destroyed. There must be better
+        // ways to handle this but the following check fixes some serious GUI
+        // bugs for now.
+        if(connector) {
+            connector.destroy();
+        }
         $(d.proxy).remove();
         $( d.available ).removeClass( "input-terminal-active" );
         $("#canvas-container").get(0).scroll_panel.stop();