pyreadline gets confused when a 'returned' process prints
There are some programs that fork to background but keep on printing
to the terminal after returning control to ipython. They are some
proprietary programs I use at work.
This confuses pyreadline, which probably thinks cursor is where it was
the last time it checked (unless changed by itself). pyreadline should
probably check the "real" situation without assuming anything.
I do not know whether this is easy to fix or reproduce. This is just a heads-up.