Skinned Cloth Editor Crashs

I have recently “dabbled” in the area of cloth rendering with unity, but I have came to a problem with the unity editor. whenever I try to use the Skinned Cloth Renderer, the unity editor suffers from drastic frame drops, almost to the point of crashing. The game runs fine when I play it, but when I try to edit what vertices act like cloth, the editor freezes. when it freezes, I get this message in the console, “Combine Mesh instance 4509 is null”. what do I do?

Only way i found is set Time.timeScale=0.00001f; for pause the game.