How to disable xbox pc controller in UEFN?

I have multiple monitors on Windows 10. UEFN 2.0 on the left one (#1). Fortnite on the right one (#2).

When I start a game session on monitor #2, after I start using the left joystick to move around in my game - a focus rectangle jumps over and starts jumping around on the menu bar of Unreal Editor on monitor #1 - and starts selecting stuff and messing around there.

This only seems to happen when Unreal Editor is running alongside Fortnite.

How can I disable Unreal Editor from recognizing the Xbox PC Controller so this doesn’t occur? I don’t have any use for the controller in UEFN. It is just for testing the game.

Thanks in advance for any assistance!!