Event in doc.onpropertychange

Event in doc.onpropertychange

This is part of the JQM source, around line 1880:

          // Whenever `document.title` changes, update the Iframe's title to
          // prettify the back/next history menu entries. Since IE sometimes
          // errors with "Unspecified error" the very first time this is set
          // (yes, very useful) wrap this with a try/catch block.
          doc.onpropertychange = function(){
            try {
              if ( event.propertyName === 'title' ) {
                iframe.document.title = doc.title;
              }
            } catch(e) {}
          };

Closure Compiler raises this error:
jquery.mobile-1.4.5.js:1881: ERROR - variable event is undeclared
              if ( event.propertyName === 'title' ) {
                   ^

I suppose Closure is right (as always).
Is this on the radar for the next version?