1. The text input field is shown form the start, no need to click.
2. The text input field is removed when no more words can be added to the
sentence.
3. When you press Enter, a word is added to the sentence (1) if there is only
one possible completion left (e.g. if you typed "airp" and the only
completion is "airport"), or (2) if what you typed exactly matches one
of the completions (e.g. if you typed "the" and the completions are
"the", "theatre" and "these").
