I'm using a third party library that uses the :nth-child-selector. It uses a notation like the following:

div:nth-child(2n + 1)

Please note the whitespaces around the plus sign. It seems like Prince does not accept the selector term if whitespaces are used. However

div:nth-child(2n+1)

works fine. According to the W3C Regex for nth-selectors whitespaces are allowed: http://www.w3.org/TR/css3-selectors/#nth-child-pseudo
As a workaround one can use a css compressor, which will remove the whitespaces. But since the library itself is quite common, as well as using spaces in nth-selectors, a fix would be great.

Thanks, we will take a look at this.

This issue has been fixed in Prince 10 rev 3, available now. Thanks for letting us know.