Universal Control not working with external display as main display
I can use Universal Control with an External monitor and a iPad Pro, if the built in screen on my MacBook Pro is active. If I close the lid on the MacBook and uses the External monitor only, Universal Control stops working and I can't control the Ipad. The pointer just stops at the end of the screen as if Universal Control isn't active.
Disabling / Enabling Universal Control doesn't help. Any ideas?
(All devices are up to date)
MacBook Pro