Window not updated after stopping the web server

[opk12]

When I press the Stop button, the activity's window does not update (the Stop button and the file list are still visible) even though the web server is stopped (cannot connect anymore).

This is the app at start.

After that I choose a file, I see this.

After that I stop the webserver, the app is still like this, instead it should "reset" to screenshot 1.