Yes, Jive Software did this. I was working for another company at the time and a colleague and I provided several enhancements to their codebase. However, befor

Yes, Jive Software did this. I was working for another company at the time and a colleague and I provided several enhancements to their codebase. However, before they would accept them we needed to get our boss to sign a document assigning all our work on their code back to them. A few months later, they announced they were taking their code in-house and leaving the open-source stuff for anyone to fork. BTW, above colleague also left to work for Jive - I believe he's still with them several years later.