Add an event equivalent to autocompleteselect that works for free text

[holizz]

After entering text, and pressing Enter, no event is fired. This makes it useless for a field that needs to accept values that were not pre-specified (i.e. tagging where many values are pre-existing but new ones are also necessary).

[Scott González]

This should be built as an extension. The ​autoSelect extension is probably a good reference for how to do this.