Nokia's enforcement of non-standard-essential patents is increasingly of concern to Google, especially when Google's closed-source, mandatory Android apps are in the crosshairs. Google has already become an intervenor in at least a handful of litigations initiated by Nokia: an ITC investigation of a Nokia complaint against HTC and at least four German lawsuits, two of which relate to Google Talk (one against HTC, one against ViewSonic) and the other two of which are about the Google Play app and content store for Android (same two defendants again). On Friday, the Mannheim Regional Court, beyond all doubt the world's leading smartphone (and tablet computer) patent forum, held a Nokia v. HTC trial to discuss claims that the Google Play store infringes EP0812120 on a "method for using services offered by a telecommunication network, a telecommunication system and a terminal for it".