Your system information

• Steam client version (build number or date): 1667429911
• Distribution (e.g. Ubuntu): Kubuntu 22.04
• Opted into Steam client beta?: [Yes/No] Yes
• Have you checked for system updates?: [Yes/No] Yes

Please describe your issue in as much detail as possible:

Testing the new beta client with "-gamepadui" option. Any non-Steam game started via the new gamepad user interface does not receive any controller input. Keyboard/mouse input is recognized in some games, in others not.
When starting the same game using the "old" user interface, it can be played with a controller.

It does not matter whether the game needs proton, or is a Linux-native game.

Steps for reproducing this issue:

1. Start Steam with "-gamepadui" option
2. Connect a controller, e.g. the Steam controller.
3. Verify that the controller is detected; navigate through the UI using the controller
4. Start a non-Steam game, e.g. the Linux-native build of "A Short Hike", added to the library as a non-Steam game.
5. Observe that controller input is not recognized.
6. Shut down Steam.
7. Restart Steam without the "-gamepadui" option.
8. Start the same non-Steam game.
9. Observe that controller input is recognized.