I've just released mitmproxy v0.12.1. This release fixes a few crashing bugs that slipped through in the previous iteration, so everyone should upgrade.
Also included are a number of small improvements. The most noticeable of these is mouse interaction for mitmproxy console - the screen capture above shows me scrolling with my mouse, clicking to view a flow and switch tabs. We pay a small price for this - users now have to hold down a modifier key (shift on some systems, alt on others) to select text in the terminal for copying and pasting. To ease users into this, we've added a warning if we detect an attempt to select text without the right modifier key.