Hi Lewis,
You could display only that dropdown option and hide all, and when they select that dropdown in the eventhandler you could enable all the other days option.
follow the steps:
1. You could create a reuse library in the ABSL to return the current day
2. Create a datamodel element in the UI designer ex: CurrentDay
3. Assign CurrentDay to the reuse library (using field transformation)
4. set visible property of the defaultset to the datamodel variable CurrentDay so that only current day dropdown option is visible and all other days dropdown options are invisible
5. on selecting current day from the dropdown, enable all other days dropdown option using UI designer script
Thanks, Pradeep.