When I debug an html file with the PHPStorm built-in server, PHPStorm first installs the Firefox extension. The next time I try to debug JS I get the following error:
The installed Firefox extension is incompatible with current PhpStorm version and will be updated. Please close Firefox if it is running and press "OK".
When I close firefox, and click ok firefox starts with the default start page.
I'm running OpenSuse 13.2 (same problems on Arch Linux) with PHPStorm 8.