Having here a strange problem with Google Maps and Firefox 8. At Google Maps Firefox didn't show the marker at the map. The Web-Console of Firefox shows the message:
[11:59:13.006] GET http://maps.gstatic.com/mapfiles/marker ... s_A_J2.png [HTTP/1.0 407 Proxy Authentication Required 0ms]
Google Sites (incl. gstatic.com) are configured in our Squid Proxy as allowed... With the Internet Explorer i don't have this problem, so this might be a problem (bug) in Firefox 8? We don't have this problem with Firefox 7.
I installed Firefox 9... Nothing changes... :-( There is still the same problems in Google Maps as i described in my first post...
That is probably a Cross-Origin Resource Sharing (CORS) issue.
Can be caused by a missing cross origin access header in the response headers from the server.
See this MozillaZine forum thread "My own Google Map icons are not visible in Firefox 8":
My problem is, that the standard markes from Google Maps didn't show. If i search for a city in Google Maps then Google is showing the Map part with the searched city but NOT a marker. I access the standard Google Maps page at http://maps.google.de. I dind't have own maps and i didn't a login to my Google account...
Works fine here with Firefox 9.
Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).
If images are missing then check that you aren't blocking images from some domains.
If an image in the list is grayed and there is a check-mark in the box "Block Images from..." then remove that mark to unblock the images from that domain.
Make sure that you do not block third-party images, the permissions.default.images pref should be 1.
For a temporary solution, please read the end of this message.
When loading the Google Maps pages, I also got 407 errors for file http://maps.gstatic.com/mapfiles/markers2/red_mark
This 407 error was received after Firefox had sent a request to get the file, but without including the proxy authentication information in the request. So getting a 407 is a normal behavior. The strange thing is that when loading a Google Maps page, there are 3 requests for the 'red_markers_A_J2.png' file, but only one of the 3 requests was missing the authentication information, as if Firefox had 'forgotten' including it.
I tested older versions of Firefox: 3.6.17 and 4.0.1. These versions do not have the problem and display the Google Maps markers correctly. They always send the proxy authentication information to the proxy.
So, it seems to be a bug introduced in recent Firefox versions. Somebody should enter it in Bugzilla if it is not present there.
To prevent the problem from happening, you can install the add-on 'Proxy Authentication 0.1.2'.
This add-on makes sure that the proxy authentication data (entered in the options of the add-on) are always sent to the proxy.
At least, it worked for me.
I have this same problem with Firefox 9.0.1, but not with explorer; "problem" = destination and location markers in Google Maps don't appear and hence can't be clicked and dragged, really limiting usefulness. Problem began a few weeks ago, maybe when Firefox updated. Haven't added any new add-ons. Tried opening Firefox in safe mode, tried the add-on posted here, tried the various Tools>Internet Options suggested here, none worked.