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 
setTimeout(() => event.target.focus({ preventScroll: false }), 0);
          },
          hidden() {
            event.target.style.visibility = detail.hidden
              ? "hidden"
              : "visible";
            storage.setValue(id, { hidden: detail.hidden });
          },
          editable() {
            event.target.disabled = !detail.editable;
          },
        };
        Object.keys(detail)
          .filter(name => name in actions)
          .forEach(name => actions[name]());
      });
      selectElement.addEventListener("input", event => {
        const value = getValue(event);
        storage.setValue(id, { value });
        this.linkService.eventBus?.dispatch("dispatcheventinsandbox", {
          source: this,
          detail: {
            id,
            name: "Keystroke",
            changeEx: value,
            willCommit: true,
            commitKey: 1,
            keyDown: false,