In editable HTML (including form controls), if you type a prefix such as "thr" and press F5 to bring up the completions popup, then press Esc to cancel, the chosen completion is not reverted and remains in the text. Moreover, if one of the completions is the empty string (e.g. if the prefix is "the") and you choose a non-empty completion in the popup then choose the empty completion, the last chosen completion isn't erased. This bug was introduced in <http://trac.webkit.org/projects/webkit/changeset/13685>.
Created attachment 13317 [details] Patch The change affects one editing test in an insignificant way.
Comment on attachment 13317 [details] Patch r=me (would be nice to add a manual test)
Landed in r19837.