Trim a video

[WebworkrNet]

I've only been using the app for a short time. Maybe I'm using it incorrectly.

1. I move the playback bar to the desired position and press the start time button. The desired time stamp is adopted. The label on the button takes over the playback position.
2. I move the playback bar to the desired end and press the button for the end time marker. But now both buttons incomprehensibly take over the end time.
3. Now I press the trim button and receive confirmation that the process was successful. To my surprise, the video is still available in its original state.

Thanks