I think that what you've asked about originally is something else - the gender of the object plays a role here as I've just learned in the sentence discussion before this one:
вон тот стол
вон та ложка
вон то яблоко
вон те ложки
Этот is used for masculine gender and это is for neutral gender. For example этот дом, это яблоко, эта женщина
This site explains it quite well -> http://www.russianforeveryone.com/Rufe/Lessons/Course1/Grammar/GramUnit6/GramUnit6_3.htm
Nothing, the program sometimes doesn't have all the alternatives yet, so you just have to notify them by clicking on the flag.