Thank you for update
@WhiteCrow_MD.In that case when you save a record in the child table,does the [Name] referenced from master table get saved in the [Name] column of child table?
When I tested, if I reference both the columns,then the thumbnail captures the [Name } properly,
At times, if in the master table, Patient Number is key and [Name] is label and if you only reference Patient ID in child table, the [Name] drop down field will show names[Name] in child table but back end will store the key.Hence the query please.
Summary: If back end spreadsheet is capturing [Name]properly in child table, the thumbnail work sproperly per my testing.
Hope this helps.