In the notebook, shift-enter, control-enter, and alt-enter all evaluate the current cell (and then do different things).
With 5.0-beta with the new prompt toolkit stuff in the terminal, alt-enter evaluates the current cell, but shift-enter and control-enter act like regular enter, i.e., they insert a new blank indented line. This is annoying if my fingers reach for the wrong one, because then I have to backspace out the indentation etc. (Also I was misremembering how the notebook worked, and was trying control-enter first, and got frustrated.)
IIRC, the only ?-enter combo we can detect in a reliable way in the terminal is alt-enter. See #9401. PTK is amazing, but some things are still not possible.
And for some reason in mintty Alt-Enter is being caught and handled the same as Alt-F11, which is the shortcut for Full Screen. Not sure why, but just thought I'd make a note of it :)
I'm told that in some terminals Alt-Enter is not detected either, and you have to do Esc, Enter (i.e. press and release escape, then press and release enter). I don't think there's much we can do about any of this, because it depends on the terminal emulator, but I'm happy to be proved wrong.
Thanks for the hint--I'll try it out. I agree there's probably not much for IPython to do, other than have an easy way to set alternate key bindings...?
Not the easiest, but it is possible: http://ipython.readthedocs.io/en/stable/config/details.html#keyboard-shortcuts