I have a couple term reference fields, one of which allows unlimited values, and one of which allows 4 values. I'm using Simple Hierarchichal Select as the widget for the unlimited one, and it lets the user select a first value, and then click 'add another item' if they need more.
If I set the other value to a simple hierarchical select widget, it shows 4 rows with no Add another button. This makes sense, but encourages the wrong behavior for this case -- I'd prefer the user select only one value, but if they need to they can add up to 4. Having 4 rows from the beginning encourages them to add 4.
I would slightly prefer to use a select list widget for this limited field, but I don't feel confident that users are comfortable with the ctrl-click to select multiple items operation, so I'd prefer a dropdown allowing them to select one at a time, with an add more button. SHS would be fine too, if I could get it to show the 'add another another item' instead of showing 4 rows from the beginning.
Is either of those operations possible? Basically I want some kind fo dropdown widget, that allows users to select one value, and require them to click add another item, to add more, up to 4.