Staircase on background commands

[majek]

Thanks for such an awesome tool. There are a couple of bugs in the terminal handling.

First, we see staircase when running background command

(for i in `seq 10`; do echo hello; sleep 0.1; done) &

Got:

prompt $ hello
                                    hello
                                         hello
                                              hello
                                                   hello
                                                        hello
                                                             hello
                                                                  hello
                                                                       hello

While in normal bash it is not staircased.