Fix the bug where you cannot use up arrow to enter the suggestions box

Review at http://gwt-code-reviews.appspot.com/239801

Review by: jlabanca@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7814 8db76d5a-ed1c-0410-87a9-c151d255dfc7