Daniel Hoppe-Jänisch has published an article titled Das Zögern zu Gunsten Dritter ("Delay in Favor of a Third Party") in GRUR 2015, 1075. Subtitled Verlust der Dringlichkeit durch Zögern gegenüber Dritten unter Berücksichtigung des Patentverletzungsverfahren ("Lack of Urgency Through Delaying an Action Against a Third Party in the Context of Patent Infringement Actions"), the article discusses among other things the Judgment of the Berlin Kammergericht (KG) of Feb. 20, 2015, 5 U 150/14-Mobilfunkgerät, in which the court vacated a preliminary injunction for lack of urgency, as evidenced by the patent owner's delay in filing its motion even though it had contacted the defendant's parent company, a Chinese firm, two years earlier about the possibility of its having sold infringing phones, and must have been aware of a sister company's having exhibited allegedly infringing phones at an exhibition in Germany a year earlier (which gave to rise to an Erstbegehungsgefahr, or danger of imminent infringement). Here is the abstract (my translation from the German):
Summary protection of rights assumes urgency. If the movant wants to invoke this urgency, it must proceed expeditiously against the opposing party. This is common knowledge. There is less notice in practice of the circumstance in which the lack of urgency can reveal itself on other grounds. In a noteworthy decision, the KG has accepted this in a case in which the movant did not proceed quickly enough against similar infringing conduct of a third party. This article undertakes an attempt at a systematization of this class of case.
Mr. Hoppe-Jänisch argues that there may be circumstances in which a movant's failure to proceed against a third party is relevant to the question of urgency, but that such failure should not give rise to a general inference of lack of urgency; and he critiques the KG's judgment for not being more precise in its reasoning. Instead, Mr. Hoppe-Jänisch proposes that courts should consider all the facts and circumstances, since there may be a range of factors motivating the movant's hesitancy towards the third party.