When multiple URLs appear in a single line in your CSS, the CSSHandler does not properly handle the path replacement. For example, if you have the line:

src: url('fonts/Franklin-Gothic-Book/15BF9F_1.eot?#iefix') format('embedded-opentype'), url('fonts/Franklin-Gothic-Book/15BF9F_1.woff') format('woff'), ....

the CSSHandler will only replace the path in the first URL  it comes to, instead of replacing all the paths. The result in this case is that the fonts are not downloaded in any browser except IE (because the one that IE uses was listed first). The workaround to this issue is to always make sure that you break up your URLs to be on multiple lines, but this is inconvenient because whenever you do a format of your CSS (Ctrl-k, Ctrl-d), Visual Studio moves them to a single line as above.

It appears that this is a known issue, because there is some commented out code in CSSHandler.cs that apparently was put in to handle this but then commented out (lines 440-466). One of the comments in this section says "this is kind of hacky, would be better if we could solve it by better regex."

I believe that this can be fixed by simply add a ? after the "<path>(.*" in the regex, like so:

Instead of: @"url\((\""|\')?(?<path>(.*))?(\""|\')?\)"

Should be: @"url\((\""|\')?(?<path>(.*?))?(\""|\')?\)"

This will force it to find each match on the line, instead of treating it as one match for the whole line. I tested this change and it seemed to work, although I must admit that I don't know with absolute certainty that this wouldn't have some other unforeseen consequences.