Remember friends, if you are using flex builder 3 and trying out various fonts for your widgets, everytime you select a font, it gets embedded into your CSS and that makes your SWF heavier. You would have noticed that with time it takes longer and longer to compile.
To get rid of this problem, ensure that you uncheck the Embedded checkbox right next to your font selection drop down. Everytime you see it checked, just uncheck it if you don’t want the font to be embedded.
Usually there are standard fonts that do not require embedding and usually they suffice for most of the business UIs.
So, if you don’t know what you are doing to make your flex design view become slower in applying style changes, you take a look at the fonts embedded to the CSS, accidentally.
Have fun with Flex and keep it simple!