LinuxCon: Keeping open source open

Yes, Microsoft filed a suit against TomTom. What I have heard is that TomTom first threatened Microsoft with a lawsuit for infringing on some software patents that TomTom held, and then Microsoft's suit against TomTom was a response to that threat. (The first stage in a patent shakedown is often to formally 'notify' the other party that they are infringing; that way, if they don't settle immediately they will be liable for triple damages for knowing infringement.)

That might be how it happened, or it might not be. But the article doesn't tell you one way or the other. It just tells you which of the two cases was first to court, which isn't very informative.