Problems with autocomplete input

First of all, sorry for my bad english.

I'm having trouble with the 'input/autocomplete' field. While I'm writing a group name, it shows the result list, no problem with that. But, if I click in an element, the GUID of the group appears in the field instead of the name.

I haven't found any documentation about this view and the code comments doesn't say anything about what gets written in the field when you click a result. Is there any way to change it?

Also, can the results be filtered by subtype? I haven't found anything about that either.