Flex Builder 3 – How to get rid of the annoying unused CSS styles warning

If you like to use one CSS file in lots of different Flex projects you’ve probably seen an annoying warning message similar to this one:

“The CSS type selector ‘ComboBox’ was not processed, because the type was not used in the application. ”

This warning will appear at compile-time if you don’t have a ComboBox in your app, for example.  I like to put lots of styles in a few CSS files and reuse them, but I really don’t need this information. So the way to get rid of these warnings is to add this line to your “Additional compiler arguments” in the “Flex Compiler” section of your project’s properties: