It seems that if you try to Schedule an Overlay Layout, and you do not have at least one campaign, the drop down list “Layout / Campign” will be blank.
Once you add a camping:
Sorry for sooo many post over the weekend.
That indeed is a bug, I’ve reported it here - https://github.com/xibosignage/xibo/issues/1148
Thank you for bringing this to our attention.
At least you had a productive weekend 