Unconditionally register $el with keyboard manager

also s/elements/additional_elements

IPython/html/static/notebook/js/widgetmanager.js

@@ -94,13 +94,13 @@
             // Have the IPython keyboard manager disable its event
             // handling so the widget can capture keyboard input.
             // Note, this is only done on the outer most widgets.
-            if (view.elements) {
-                for (var i = 0; i < view.elements.length; i++) {
-                    IPython.keyboard_manager.register_events(view.elements[i]);
+            IPython.keyboard_manager.register_events(view.$el);
+            
+            if (view.additional_elements) {
+                for (var i = 0; i < view.additional_elements.length; i++) {
+                    IPython.keyboard_manager.register_events(view.additional_elements[i]);
                 }
-            } else {
-                IPython.keyboard_manager.register_events(view.$el);
-            }
+            } 
         };
 
         WidgetManager.prototype.create_view = function(model, options, view) {

IPython/html/static/notebook/js/widgets/widget_container.js

@@ -81,7 +81,7 @@ define(["notebook/js/widgets/widget"], function(WidgetManager) {
             // need to know about all of the top-level widgets.  The IPython
             // widget manager uses this to register the elements with the
             // keyboard manager.
-            this.elements = [this.$el, this.$window]
+            this.additional_elements = [this.$window]
 
             this.$title_bar = $('<div />')
                 .addClass('popover-title')