UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:52.0) Gecko/20100101 Firefox/52.0

Steps to reproduce the problem:
1. Clear the browser's cache and exit the browser
2. Start the browser and install the attached Chrome extension
3. Visit http://www.tamarack-software.com/tgptest

What is the expected behavior?
The file http://www.tamarack-software.com/files/versioninfo.wtk is downloaded by the extension.

What went wrong?
The browser console shows the error message "XMLHttpRequest cannot load http://www.tamarack-software.com/files/versioninfo.wtk.  No 'Access-Control-Allow-Origin' header is present on the requested resource.  Origin 'chrome-extension://lhojjcofegcnofaknffnhbgmgbgonpdb' is therefore not allowed access."

Did this work before? Yes Uncertain

Does this work in other browsers? Yes

Chrome version: 57.0.2987.113  Channel: stable
OS Version: 7
Flash Version: 

This is a regression from earlier versions of the browser.  In particular, I can confirm that the behavior is not present in 49.0.2623.112, but is present in 56.0.2924 and newer.  Based on the timing of bug reports I've received, I suspect the breakage happened sometime between version 55 and 56.

The behavior is intermittent and may be related to caching.  In particular, re-loading the page permits a subsequent request for the file to succeed, while applying anti-caching techniques cause requests for the file to always fail.

This may be related to this report on StackOverflow: http://stackoverflow.com/questions/38770686/chrome-extension-suddenly-shows-cross-origin-error
 

Deleted: nptgeq_extension-1.2-minimal-example.zip 13.9 KB

nptgeq_extension-1.2-minimal-example.zip 13.9 KB Download