Bug 587909 is improving the location bar results by removing some of the extra noise that is shown for each result. As a follow-up bug, we should start only showing matched tags on the results (instead of all the tags that a site may have).
I think it may be confusing to a user if they don't see the other tags they've assigned to a page. This would also add more overhead on every keystroke since we'd have to re-filter the tag list. Tags being added/removed as you're typing could add more visual distraction. In the past we've tried to minimize similar movement such as reducing how often we update the results in the dropdown.
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