Adobe is suing Macromedia over the use of user interface elements it claims are covered by a patent Adobe filed in 1994.
The suit, filed with the District Court of Delaware, alleges that Macromedia uses of "tabbed palettes" infringes this patent. In a statement, Adobe president Bruce Chizen said "Adobe will not be the R&D department for its competitors. Our patent and other aspects of our user interface are ... essential to differentiate our products and brand from others."
Macromedia responded saying the patent is "invalid and unenforcable" [sic], and that Adobe had contacted them about the issue twice before in 1996 - the year the patent was approved - and again last year.
Adobe's patent has been cited in nine subsequent patents granted to Microsoft, Adobe (again) Apple, HP, Kai Krause of Kai's Power Tools fame, and the then-Starfish (now owned by Motorola) for its Dashboard utility.
Adobe says it has created a website to defend its use of the patent. ®