HI!,

You can do it by assigning event listeners for your particular key in the popup widget. Here is an example of code to do in the show function of popup widget:

show: function(){

    window.document.body.addEventListener('keydown',this.keyboard_keydown_handler);

    this._super();

},

where "this.keyboard_keydown_handler" is a function in the widget.

Hope this helps!

Cheers.