Reporter: Richard
[Submitted to the original trac issue database at 12.33pm, Thursday, 7th April 2011]

(from IRC)

A) select a way that has two or more tags. In the last tag, change the key to something that a) is higher up in the list and b) autocomplete knows about. For example, if highway=motorway layer=1 type "motorway" in the box with "layer" in it and press tab. The tag you are typing into disappears (correctly), but AutoComplete blows up

B) select a way that has 3 or more tags, and edit tag number #2 giving it the key from #1 (well, pick N where N < Nmax and use Kt where t < N). When you press tab, the key disappears but you are editing the value from tag #2 in original position, but the tags have condensed by one so you're editing the wrong value.