Record what returned and what changed
Note whether the application reopened automatically when DeX started, whether its window changed size or position, and whether the programme itself resumed. These are three observations: app membership in the session, window layout and media playback state.
Samsung says the newer interface relaunches apps from the previous DeX session. It separately says individual app windows no longer retain their old dimensions and position when reopened. A returning app in a default-sized window is therefore consistent with both documented behaviours.
Compare a fresh window deliberately
On the supported software version, resize one app window, close it after preserving work, then reopen it and observe the layout. Keep that comparison separate from restarting the whole phone or reinstalling the media app. The question is whether a newly opened window retains its geometry.
If a previously open app appears at DeX startup, inspect its visible controls before assuming an unattended programme will play. Samsung’s app-session description does not promise that every media service restores an exact timestamp, track selection or autoplay decision. Those remain separate application and account observations.
Choose a workable viewing arrangement
Arrange the reopened window for the current screen and confirm the actual programme position. If the app itself is missing or fails to launch, record that different failure rather than attributing it solely to default window geometry. Keep the desktop’s simultaneous-app limits in mind when opening additional windows.
For help, provide the Galaxy model, One UI version, app launch behaviour, before-and-after layout and playback result. This avoids treating restored app presence as a guarantee of saved window placement or resumed media. The distinction makes a support report specific enough to separate documented desktop design from an application that is losing its own viewing state.