Using non-standard css properties in GWT

Sometimes you'll want to use a non-standard CSS property in GWT via CSSResource - say to use rounded-corners on your borders using -moz-border-radius and -webkit-border-radius.

However, if you just plonk those properties in your CSSResource you're in for some warnings. GWT doesn't like property names that start with "-". The solution is very simple: escape the leading "-" with a "\", e.g. \-moz-border-radius: 5px.