This extension causes the event.shiftKey, event.altKey and event.ctrlKey properties on the click event of buttons, input buttons and input submit buttons to always be false regardless of if they are held.
The alt key does actually work on its own, but combined with other modifier keys it doesn't.
I almost always submit forms by pressing enter rather than clicking a submit button, and this extension doesn't seem to apply to those. However the Greasemonkey script referred to in another review does, so that's worth a look.
Thanks for this addon! It works fine in Firefox 13.0.1. By the way, Mozilla.org, this is really dumb: "Please do not post bug reports in reviews. We do not make your email address available to add-on developers." People are not going to create dozens of registrations for all the addons they use in order to make bug reports. So allow us reviewers to choose to make our email address available privately to developers.
When loading Fx I see this warning in the error console:
Warning: Bootstrapped manifest not allowed to use 'overlay' directive. Source File: jar:file:///C:/path/to/my/Firefox/profile/extensions/%7B421e87b4-d3d2-49c8-b08f-b83f4dc88444%7D.xpi!/chrome.manifest Line: 3