Send messages on widget addition and deletion

src/ScalarMessaging.js

@@ -338,6 +338,12 @@ function setWidget(event, roomId) {
         sendResponse(event, {
             success: true,
         });
+
+        if (widgetUrl !== null) {
+            client.sendTextMessage(roomId, `Added ${widgetType} widget - ${widgetUrl}`);
+        } else {
+            client.sendTextMessage(roomId, `Removed ${widgetType} widget`);
+        }
     }, (err) => {
         sendError(event, _t('Failed to send request.'), err);
     });

src/components/views/rooms/RoomHeader.js

@@ -121,7 +121,9 @@ module.exports = React.createClass({
                     this.scalarClient.getScalarInterfaceUrlForRoom(this.props.room.roomId) :
                     null,
             onFinished: ()=>{
-                this.props.onCancelClick(ev);
+                if (this.props.onCancelClick) {
+                    this.props.onCancelClick(ev);
+                }
             },
         }, "mx_IntegrationsManager");
     },