When you press Enter at this point it will "confirm" completion instead of going to the new line.
But there is nothing to complete, because I typed 'then' manually and expect Enter to start a new line. To do that I have to hit the Enter twice.
After 'then' I have to hit the Enter twice for 'else' and even for 'end'
The language is Lua, I haven't tried with other languages (just trying Sublime Text out). This is in Sublime Text 2 beta 2181.
Oh, forgot to say that I'm very impressed with the author's sense of style and attention to details.