So you just finish your awesome Flex app and unleash it into the wild. It’s great, except for an annoying blue flash that happens before the movie renders. Despite setting the background color to many things when embedding your SWF, it still flashes blue. It only happens in some browsers, but it’s enough to be a total eyesore.

This is because Flex has a “default background color” that it likes to present to the user before any rendering is done. The busier the web page, the more noticeable this flash is.

You’d think Flex would offer an easy way to access this property and change it, but it doesn’t (at least as far as I know). What you can do however, is change the color using a compiler option. I know, compiler options are the bandaid for every annoying thing with Flex these days, but at least they are available.

-default-background-color=0xffffff

This will change the color to white. I would make this color whatever value your most common backgrounds are that your SWF goes on top of. You could probably sidestep this with using wmode=”transparent” but that’s a rather drastic measure to take for just fixing an annoyance such as this.