Key combination ALT and S is commonly used to save or submit data in web application, such as Exact Online, phpBB and vBulletin. Since Mozilla Firefox 2.0 this is not working anymore.
This can be fixed by editing two settings in the advanced settings of Firefox.
- In Firefox, visit about:config
- Change ui.key.chromeAccess to 5
- Change ui.key.contentAccess to 4
The changes are immediately effective, no need to close and reopen the application.