Show tag editor for untagged entities that aren't new

Fixes #991.

js/id/core/entity.js

@@ -63,6 +63,10 @@ iD.Entity.prototype = {
         return iD.Entity.id.toOSM(this.id);
     },
 
+    isNew: function() {
+        return this.osmId() < 0;
+    },
+
     update: function(attrs) {
         return iD.Entity(this, attrs);
     },

js/id/modes/select.js

@@ -4,7 +4,7 @@ iD.modes.Select = function(context, selection, initial) {
         button: 'browse'
     };
 
-    var showgrid = singular() && !_.without(Object.keys(singular().tags), 'area').length;
+    var showgrid = singular() && singular().isNew() && _.without(Object.keys(singular().tags), 'area').length === 0;
 
     var inspector = iD.ui.Inspector(context).initial(showgrid),
         keybinding = d3.keybinding('select'),