If there is a CSS property that you want to ignore then you can tell CSS HTML Validator to ignore it if you're using the pro or enterprise edition.

The easiest way may be to use the special ignore comments described in the Ignore Parts of a Document topic, but if that method is not suitable for your needs then you can create (if you don't have one already) a 'user functions' file and specify this file in the Config Files Page in the Validator Engine Options.

Let's say you want to ignore a CSS property named "ignore-this".  In the user functions file, create this function (or add the code to the function if the function already exists in a user functions file):

function onUnknownCSSPropertyMessage() {
 if matchNoCase($oucpm_property,"ignore-this") {
  $oucpm_msgflags=0;
  setValueString(12,$oucpm_property);
 }

If you want to add more CSS properties to ignore, then add them to the end of the parameters of the matchNoCase() function, separating each string with a comma. Example: matchNoCase($oucpm_property,"ignore-this","ignore-this-too")

You can also display your own message when an unknown CSS property is encountered. See the onUnknownCSSPropertyMessage() topic for more information.

hmtoggle_plus1Alternate method (an older method which is not recommended)