KeyPress callback elements [3 6] should be scalars

[mbaas2]

(I'm not sure how faithful we want to be wrt to those details - so feel free to close if you think this is overkill)

DemoPassword: on entering the value "H" into the field "Password", the KeyPresscallback is called with its 3d element being the character vector H.
The doc says: "If the keystroke resolves to a character, the Input Code is a character scalar."

[mbaas2]

P.S: Also the shift state (6th element) should be a integer scalar!