This is a really irritating bug caused by some obscure issue between Firefox and Flash.

When my Flex app loads up the Security Settings Panel (trying to grab the camera), OS X users weren't able to click the 'allow' button in the panel. Or anything in the panel, for that matter.

The fix? An absurd, hack-y JS workaround. I'll post when I get the time to figure out something better. This works for me for now, though.

1) Positioning the containing element of the flash as "fixed":
2) Making sure there is no scrollbar on the browser window.

This one had annoyed me for quite some time, very happy to finally have found a fix:

Every time Gmail refreshed, it would reload all the star icons one by one, and would freeze up that tab until all the visible star icons were reloaded. This would make me wait for all the stars to load before I could go back to work on another tab...BOOO.

Here's the fix:

1) In the location bar, go to about:config
2) Search for browser.cache.memory.enable
3) Change it to "true"