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 hasRan = this.runActions(source, source, event, "Validate");
    if (event.rc) {
      if (hasRan) {
        source.wrapped.value = event.value;
      } else {
        source.obj.value = event.value;
      }
      if (this._document.obj.calculate) {
        this.runCalculate(source, event);
      }
      event.value = source.obj.value;
      this.runActions(source, source, event, "Format");
      source.wrapped.valueAsString = event.value;
    }
  }
  runActions(source, target, event, eventName) {
    event.source = source.wrapped;
    event.target = target.wrapped;
    event.name = eventName;
    event.targetName = target.obj.name;
    event.rc = true;
    return target.obj._runActions(event);
  }
  calculateNow() {