Fix Layer's Popup and typo in Popup class

Author: martinRenou

js/src/layers/Layer.js

@@ -1,5 +1,7 @@
 var widgets = require('@jupyter-widgets/base');
 var _ = require('underscore');
+var PMessaging = require('@phosphor/messaging');
+var PWidgets = require('@phosphor/widgets');
 var L = require('../leaflet.js');
 var utils = require('../utils.js')
 
@@ -91,12 +93,9 @@ var LeafletLayerView = utils.LeafletWidgetView.extend({
             var that = this;
             this.popup_content_promise = this.popup_content_promise.then(function() {
                 return that.create_child_view(value).then(function(view) {
+                    PMessaging.MessageLoop.sendMessage(view.pWidget, PWidgets.Widget.Msg.BeforeAttach);
                     that.obj.bindPopup(view.el, that.popup_options());
-
-                    // Trigger the displayed event of the child view.
-                    that.displayed.then(function() {
-                        view.trigger('displayed', that);
-                    });
+                    PMessaging.MessageLoop.sendMessage(view.pWidget, PWidgets.Widget.Msg.AfterAttach);
 
                     that.popup_content = view;
                     that.trigger('popup_content:created');

js/src/layers/Popup.js

@@ -60,7 +60,7 @@ var LeafletPopupView = LeafletUILayerView.extend({
             this.child_promise = this.child_promise.then(function() {
                 return that.create_child_view(value).then(function(view) {
                     PMessaging.MessageLoop.sendMessage(view.pWidget, PWidgets.Widget.Msg.BeforeAttach);
-                    thar.obj.setContent(view.el);
+                    that.obj.setContent(view.el);
                     PMessaging.MessageLoop.sendMessage(view.pWidget, PWidgets.Widget.Msg.AfterAttach);
                     that.force_update();
                     that.child = view;