Apparently, just about every graphical user interface that Apple churns out was patented and put on lock down years decades ago, as now a patent holding firm (IP Innovation) has filed a much-delayed lawsuit against the Cupertino-based outfit over its use of an OS interface. The patent in question dates back to 1984 via references in a 1991 filing by Xerox, which actually linked to GUI concepts drafted in the 1970s on the company's Alto workstations. Amazingly, the folks involved have just got around to slapping a lawsuit on Apple for selling OS X with "workspaces provided by an object-based user interface that appear to share windows and other display objects." The incredibly vague wording could realistically be used to target nearly every major OS that we've seen, and considering that Apple and Xerox already went a round in the legal ring back in 1989 over similar issues, this one certainly seems to lack substance. As expected, the $20 million claim was filed in the patent troll haven that is Marshall, Texas, and while we haven't heard word from an Apple spokesperson regarding the matter, we'd say there's a more pressing matter on the table for Jobs & Co. right now anyway.