From: PC Mag's article
DecoderPro files are available for free download via open source Web site SourceForge, which is maintained by Jacobsen. Anyone can download DecoderPro files, but if they use those files for another project, they must include a notice that says it was originally developed by JMRI and note any changes made to the files. Matthew Katzer and Kamind Associates offer a competing product known as the Decoder Commander. During its development, a former employee allegedly downloaded the DecoderPro files and used portions of it in the Decoder Commander software. Katzer and Kamind, however, did not comply with the DecoderPro licensing rules. Their product did not include the authors' names, the JMRI copyright notices, references to the copying file, a notice identifying SourceForge or JMRI as the original source of the definition files, or a description of how the files or computer code had been changed from the original. Jacobsen sued to get an injunction against the distribution of Decoder Commander because, he said, the company's lack of attribution constituted copyright infringement.
Here's JRMI's story
This whole situation raises some serious questions. On the patent side, how many patents are based off prior art and at what point do patents become issuable if they are based on prior art, but not to the full extent of the patent? Most patents do include prior art. Also, is every clause in a software license enforceable? Its almost like someone needs to do a sanity check on submitted patents and provide examples of prior art to the USTPO, especially from open source projects."