What new or enhanced feature are you proposing?

It looks like you launched a new feature where the search box (e.g. on crbug.com) now autocompletes what I type. That's great, except that

a) hitting enter fills in the first autocomplete entry and
b) the autocomplete entries are never what I want.

Hence, I now need to click search instead of hitting enter, which is very annoying.

Example: I used to add "thakis" (my handle) to queries to search for bugs I own, commented on, or have starred, and that worked fine. Now, when I type "thakis<enter>", "owner:thakis@chromium.org" gets added to the search box, which isn't what I want at all.

It's up to you how to fix this ("don't just give them faster horses" and all), but easy fixes would be to let enter not select from the autocomplete if the user never explicitly changed the selection in the popup, or to not autocomplete handles to "owner:handle@domain".

What goal would this enhancement help you achieve?

It would restore sanity to my bug searching workflow.