[IE 11] Multiple definitions of a property not allowed in strict mode

[janzenz]

I see this error on IE 11:

SCRIPT1046: Multiple definitions of a property not allowed in strict mode

and it points to this line

And this is what the IE 11 console reports:

                _react2['default'].createElement(
                    'div',
                    { className: 'modal__control-item modal__close', role: 'button', tabIndex: '0', onClick: this.requestClose, tabIndex: '0' },
                    'W'
                )

Notice that the tabIndex repeated twice.