Apple has been sued for using patented technology in its Mac OS X 10.4 "Tiger".

According to AppleInsider, the operating system's nearly universal use of tabs treads on a patent owned by intellectual property agency IP Innovation.

The suit claims that Apple has engaged in 'willful and deliberate' infringement of a computer control patent by selling its current Tiger operating system."

The company wants $20 million and an injunction that would prevent the California-based defendant from infringing on the patent, essentially blocking Apple from continuing to sell its current edition of Mac OS X and any future editions that might draw on the supposed infringements.

More here.