A company called Cygnus Systems has sued bigwigs Microsoft, Apple, and Google over icon software patent infringement, reports Macworld.

The company claims that it holds the (recently acquired) patent rights on a common file preview feature used by browsers and operating systems to show users small snapshots of the files before they are opened.

Windows Vista, Internet Explorer 8, Apple's Finder and Cover Flow, and Google Chrome use this feature, the company said in court filings.

Cygnus owns the rights to a System and method for iconic software environment management patent (# 7346850) which it had applied for in 2001 and was granted by the U.S. Patent and Trademark Office in March of this year.

"We've identified many other potentially infringing products that we're investigating," said Matt McAndrews, a partner with the law firm representing Cygnus. So it seems like Cygnus isn't done suing with the big three; there will be other companies that will join the list.