Let's assume we have a value list X referring to values from a first field A and a second field B. Let's further assume that the checkbox "Show values only from second field" is checked on value list X.
We now add a field to our layout, where we want to select values from value list X.
Apart from a lot of more complicated methods to offer choices to users, we have two simple methods: Pop-up menus and Drop-down list menus.
Pop-up menus always show the values of field B (during selection and after selection). However, Pop-up menus become impractical if the value list consists of more than about 30 entries because you cannot scroll across the selection dialog.
Drop-down list menus easily handle value lists with hundreds of entries. They show value B during selection and value A after selection. There is no way of changing that. The most annoying case is if field A refers to an ID value. So what the users sees after selection is some convoluted ID value. As a consequence of this, I have been working around this issues for years. Daily. Always. Again and again. Probably many of you out there have been forced to invent creative ways to present selections to users, too.
I therefore wish there was an option on Drop-down list fields to choose which value - A or B - should be displayed after selection.