Found in Firefox 5 (one of our clients standardised on it).
Slick.Finder.js, line 217
context.compareDocumentPosition throws NS_ERROR_ILLEGAL_VALUE when passed null. Simply adding in "if (node === null) return false;" fixes the problem for me. Should I make a pull request?
Do you have an example of that? I think the problem is not in this method, but at the moment we pass null to it, we shouldn't be passing null to it. If you could help with a jsfiddle or something, would be awesome!