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 
const xref = new XRefMock([
        { ref: buttonWidgetRef, data: buttonWidgetDict },
      ]);
      AnnotationFactory.create(
        xref,
        buttonWidgetRef,
        pdfManagerMock,
        idFactoryMock
      ).then(({ data }) => {
        expect(data.annotationType).toEqual(AnnotationType.WIDGET);
        expect(data.checkBox).toEqual(false);
        expect(data.radioButton).toEqual(true);
        expect(data.fieldValue).toEqual("1");
        expect(data.buttonValue).toEqual("2");
        done();
      }, done.fail);
    });
    it("should handle radio buttons with a field value not an ascii string", function (done) {
      const parentDict = new Dict();
      parentDict.set("V", Name.get("\x91I=\x91\xf0\x93\xe0\x97e3"));
      const normalAppearanceStateDict = new Dict();
      normalAppearanceStateDict.set("\x91I=\x91\xf0\x93\xe0\x97e3", null);
      const appearanceStatesDict = new Dict();
      appearanceStatesDict.set("N", normalAppearanceStateDict);
      buttonWidgetDict.set("Ff", AnnotationFieldFlag.RADIO);
      buttonWidgetDict.set("Parent", parentDict);
      buttonWidgetDict.set("AP", appearanceStatesDict);
      const buttonWidgetRef = Ref.get(124, 0);
      const xref = new XRefMock([
        { ref: buttonWidgetRef, data: buttonWidgetDict },