There have been new developments in the ongoing legal tussle between Salesforce and Microsoft. Last month, Microsoft fired the first salvo when it accused Salesforce of stealing its technology. This week, Salesforce retaliated with a lawsuit of its own. The company is accusing Microsoft of infringing five of its patents.

Microsoft's lawsuit was filed in a Seattle federal court, and accuses Salesforce of using Microsoft's technology in toolbars, software menus and graphical interface features. Microsoft also alleges that Salesforce was in violation of nine of its patents. This week, Salesforce filed a lawsuit against Microsoft, alleging that the Redmond-based company violated five of its patents. According to the lawsuit, a number of Microsoft's products, including its SharePoint software, violated patents that belonged to Salesforce. That lawsuit has been filed in the US District Court for the District of Delaware.

The spat between the two software giants has carried on even outside the courtroom. In fact, representatives of both companies can be seen outside each other's events, handing out flyers. Salesforce chief executive Mark Benioff hasn't held back in his attacks against Microsoft's. Earlier this week, Benioff spoke at a launch in San Jose in California for the social networking app for businesses, Chatter. Benioff has likened Microsoft to a dinosaur that just isn't able to keep pace with new technologies.

Obviously, lawsuits that involve patent infringement issues in the software field require not just a strong understanding of patent laws, but also a technical understanding of the software product issues involved. Besides, there also aspects of copyright law that can enter the picture. Software patent infringement issues are even more delicate issues, because it's not just software code or text that are involved, but also the novelty of the idea, the functionality of the software or its behavior. All of these issues have to be considered by a California defense litigation lawyer.