Problem

The user tries to use Steam to play gameplay videos but is unable to play them in full screen.

Cause:

The scaling and the layout size of the Windows system is not set to "100%", resulting in an incompatibility issue between Steam and the Windows system.

Solution

Perform the following steps to change the scaling and the layout size of the Steam app:

1. Right-click Steam and select Properties.
2. Click Compatibility.
3. Select Change high DPI settings.
4. Tick the box next to Override high DPI scaling behavior..
5. Select System under Scaling performed by:.
6. Click OK then restart Steam.
7. You will then be prompted with a message indicating that Steam is being run in a Windows-compatible manner. Then click CONTINUE to proceed.

Huawei has reported this issue to Steam. Stay tuned for further updates to Steam.