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 
});
  describe("PopupAnnotation", function () {
    it("should inherit properties from its parent", function (done) {
      const parentDict = new Dict();
      parentDict.set("Type", Name.get("Annot"));
      parentDict.set("Subtype", Name.get("Text"));
      parentDict.set("M", "D:20190423");
      parentDict.set("C", [0, 0, 1]);
      const pupDict = new Dict();
      pupDict.set("Type", Name.get("Annot"));
      pupDict.set("Subtype", Name.get("Popup"));
      pupDict.set("Parent", parentDict);
      const pupRef = Ref.get(13, 0);
      const xref = new XRefMock([{ ref: pupRef, data: pupDict }]);
      AnnotationFactory.create(
        xref,
        pupRef,
        pdfManagerMock,
        idFactoryMock
      ).then(({ data, viewable }) => {
        expect(data.annotationType).toEqual(AnnotationType.POPUP);
        expect(data.modificationDate).toEqual("D:20190423");
        expect(data.color).toEqual(new Uint8ClampedArray([0, 0, 255]));
        done();
      }, done.fail);
    });
    it("should handle missing parent properties", function (done) {
      const parentDict = new Dict();
      parentDict.set("Type", Name.get("Annot"));
      parentDict.set("Subtype", Name.get("Text"));