It is not just some elements of Chabad that still believe their leader is Mashiach even though he is dead. In my neighborhood, some individual or individuals have been putting up posters and stickers claiming the dead leader of The Na, Nach, Nachman sect of Breslov is Mashiach!
I am very far from being a member of either movements. In fact I, like the Chatam Sofer, think that most of the Zohar is not from Rabbi Shimon Bar Yochai which knocks down the foundations of the various chassidic movements. Nevertheless, I do expect and demand that individuals who are part of the more respectable branches of Chabad and Breslov to come out and denounce, those individuals who are turning dead Chassidic leaders into the Mashiach.
Being quiet is not enough in my opinion to separate yourselves from these "messianists".