Global Regions in Upfront Builder

Hi, when I click on Edit Global Regions in Theme Settings, a box popups which shows all my global regions, but none of them are clickable. There doesn't seem to be a way to actually edit the global regions? I hover over each one and the background changes color, but nothing that will let me edit the region?

Also, is it possible to convert an existing region into a Global region after I already created it?

Thanks & regards,
Chrissy