Three Screens Apple Pro Studio

I want the FCPX 'browser' screen that is on the right to open on the left.

I can move the centre screen to the left, but the browser stays on the right screen and when I move the centre screen to the right the browser sits on the middle screen.

I tried swapping the USB-c cables, and it worked... until it restarted and went back to the wrong side.

How do I get the browser on the left-hand screen... please?