Strange but reproducible behaviour in FMP12 (v01 and v02) which always worked well in FMP11.
Setup is as follows:
A value list is build in an indexed text field with auto-entry calculation (i.e. not a calculation field) via UI-1 in the Data file.
When I call the value list in UI-2, it will not come up, except when I call it first in UI-1 layout.
The same solution in FMP11 never showed this behaviour. I noticed some bugfixes in FMP12v2 today related to ValueList behaviour, but this one does not fit in one of FMI's descriptions.