twistedcubic writes "Red Hat and Novell have been sued for patent infringement in Texas by IP Innovation, LLC. and Technology Licensing Corporation. On October 9, IP Innovation filed suit claiming Red Hat and Novell violated U.S. patents 5072412, 5533183, and 5394521. The patents were originally assigned to Xerox Corporation. A cursory look suggests the patents involve virtual workspaces and sticky windows with different properties in each virtual workspace. Groklaw has the scoop."