PuDB isn't hidden while code running in terminal.app

Hi!

I have a problem when long-running python code. I don't see my blank terminal. Instead I see PuDB and whatever I write starts going to a random place (e.g., the bottom of breakpoints or variables) while python code runs if I use terminal.app. This is not a problem in iTerm 2, but only when using tmux.

I was following the [UC Davis Tutorial](http://heather.cs.ucdavis.edu/~matloff/pudb.html#quickpic) and in Quick Pictorial Introduction, where the white terminal background shows up in the screen shots, what I get diverges from what the tutorial shows. Another divergence is that when I hit `ctrl-c` as the code runs, I don't get an exception.

Thanks!

Start by reproducing the behavior with long-running Python code in PuDB under terminal.app and tmux, then compare it with iTerm2 as described. Check whether the terminal remains visible while code runs and whether Ctrl-C produces an exception; done means the behavior matches the expected blank terminal and interrupt handling.

Written by the indexing model from the issue text.