Q: How come sometimes the enter button submits the question but sometimes it just adds a new line
A: because i've found that when you type a short question, you are more likely to expect 'enter' to send. and when you type a much longer question, you are more likely to want to use line breaks and then potentially be horrified when your question is sent and taken away from you too soon. so enter works to send short questions but not long questions. which seems to result in far fewer enter-related mis-haps then there ever were when it was all one or the other