In the following spots a "MouseUp" eventName is being used, which does look inconsistent considering that the "Mouse Down"/"Mouse Enter"/"Mouse Exit" eventNames all have a space in them.
Is this inconsistency actually expected, or is it a simple typo? If the former, then a comment explaining *why* would be appropriate; otherwise we should just fix this :-)

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L806

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L945

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1034

 - https://github.com/mozilla/pdf.js/blob/25b84ce84c95ba06d1ee57e578672048269c39c1/src/display/annotation_layer.js#L1168

/cc @calixteman 
event.target.disabled = !detail.editable;
          },
        };
        Object.keys(detail)
          .filter(name => name in actions)
          .forEach(name => actions[name]());
      });
      this._setEventListeners(
        element,
        [
          ["change", "Validate"],
          ["change", "Action"],
          ["focus", "Focus"],
          ["blur", "Blur"],
          ["mousedown", "Mouse Down"],
          ["mouseenter", "Mouse Enter"],
          ["mouseleave", "Mouse Exit"],
          ["mouseup", "MouseUp"],
        ],
        event => event.target.checked
      );
    }
    this.container.appendChild(element);
    return this.container;
  }
}
class RadioButtonWidgetAnnotationElement extends WidgetAnnotationElement {