I cannot figure out why, but, in a tree/planting projects database, I have a fairly simply data model where I have one polygon layer to symbolize the area/project (eg. Maple Oak Park, John Smith School), and a point layer to symbolize the trees planted in that area/project. I created a relation between the two layers using the area/project name as the join field (image #1).
I want to then add this relation to the form for the area/project layer, so that all the trees associated to the area/project appear on the form. See image #3 for an example where this worked for me a few months ago on another set of layers. However, for some reason the relation simply does not appear as an option in the attributes form (image #2).