The way that sidebar widgets open and close is inconsistent. Setting a message action on a Button to toggle the sidebar makes it slide smoothly into and out of view, but using the same message action on a List widget causes it to "snap" open and shut abruptly. It's a minor complaint but an important element of the user experience is polish, and no matter how well designed the app is this unavoidable lack of polish reflects poorly on the organization creating the Experience.
