[hide-keyboard] key throws an exception and then fails to close the keyboard

[timmckague]

Description

The [hide-keyboard] key throws an exception and then fails to close the keyboard.

The error thrown is

TypeError: mathfield.focus is not a function

Steps to Reproduce

I added a custom keyboard that uses the [hide-keyboard] key

Actual Behavior

When I click the [hide-keyboard] button a TypeError is thrown and the keyboard does not close.

Expected Behavior

I would expect the keyboard to close and no error to be thrown.

Environment

MathLive version 0.96.0 and 0.95.5

Operating System macOS

Browser Safari and Chrome