We just discovered a small nuisance/bug in FMPA 16 (macOS 10.12.6). This might be by design, but it feels like a bug to us.
We are trying to apply conditional formatting to a whole bunch of fields. Normally, in layout mode, we can hold down the shift key while clicking on multiple fields to select all of those fields simultaneously.
However, under one circumstance, this does not work:
1. Put a container field on your layout.
2. Turn this container field into a button and attach a script to it.
3. Open up the "Layout Objects" palette.
4. Within the "Layout Objects" palette, find that container field (which is nested within a grouped button) and click on the name of the field within the "Layout Objects" palette. You will notice that the container field is now highlighted on your layout. Everything is perfect so far!
5. BUT -- return to your layout and try to shift-click on additional fields. No other fields get selected.