Seen with Tiger 7.4.7

I noticed that the map did not display when I viewed an album with GPX tracks from a remote server. After some investigation, I pinpointed the problem:

In the loadOverlays function ( laza.addmap.js/laza.adddosmmap.js:164 ), xhr.responseXML is null in the response returned by the server! I think the server is returning a malformed response because this problem doesn't occur with the local album or other servers.

A possible fix, according to https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/responseXML, is to force the MIME type in the request:

xhr.open('GET', overlays[0], true);
xhr.overrideMimeType("text/xml");  // Forces the response to be parsed as XML

I tested it, it works