Currently the user has to manually pop up completion window in situations where it makes sense to pop up completion automatically. For example, 
typing...

JFrame f = new |

... should popup completion automatically.

It  would make sense to popup completion automatically also when writing in a new line (inside a method and/or outside). But this would require to make 
completion window faster and maybe even smaller. Also the Javadoc window is too big, which might cause problems.

Something to consider.