How to get the current speed of playback

You cannot read the speed for the playback in the main window.

You can subscribe to SmartClient.PlaybackIndication, this will give a message whenever playback speed is changed.

If you are in another window (NOT main) you can read the speed in the view item like this:

private void Button_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            FQID pbcFQID = this.WindowInformation.PlaybackControllerFQID; 
            var pbc = ClientControl.Instance.GetPlaybackController(pbcFQID);
            double speed= pbc.PlaybackSpeed;
            MessageBox.Show("Speed " + speed.ToString());
        }