Resolve UI fullscreen problems

I'm running Resolve 15 on a late 2015 iMac 5K.

This isn't something I've encountered with previous releases but I can't get the Resolve UI to run fullscreen. If I enable this in the Workspace menu, resolve shrinks down on the desktop as per photo.

I'm running a Blackmagic Mini Monitor which is working fine to second display.

I've tried a whole range of fixes but nothing as yet.

Any suggestion appreciated.

Cheers

[img]/Users/Farmhouse/Desktop/Resolve_UI_issue.png[/img]

[Peter Chamberlain]

Can you post the image to a third party storage location, like dropbox?