Auto-complete is partially broken

[rickmastfan67]

Steps to reproduce:

1. Load (or create) any way/node and make sure it's selected.
2. Click the "+Add" button to add a tag.
3. Start typing a "key".
4. Intentionally mistype the "key".
5. Delete the mistyped part of the "key" and try to get auto-complete to finish the "key".

Expected results:
Auto-compete would give me at least one key (or value) for auto-completing.

What happens:
Auto-compete is broken and you have to manually finish typing the key (or value).

This happens in both the "key" and "value" boxes.

Example:
Here's a tag that you can easily do to verify the problem:
Type "n3" instead of "name" into the "key" box. When you delete the "3" and type "a" to trigger the auto-complete, it will not work.

This bug will not trigger as long as you don't misspell anything.