The "Display all N possibilities? (y or n)" prompt appears at the end of the command line

[rinswind]

It seems that the "Display all N possibilities? (y or n)" prompt always appears on the same line as the command prompt. This is quite confusing since the prompt and the already typed text are merged in one continuous string that is hard to read. Can the prompt appear a new line?
I am not certain if this is not caused by the way I use jline - if so I'd be grateful for any advice on how to fix this.