Remove vertex group not working

Previously I had done some simple cloth animations, with one edge of vertices selected and put into a new group, which I then pinned. I then added a vertex weight edit modifier. At a point during the animation, I added a keyframe to tick the “Group Remove” box in the modifier panel. The remove threshold I set to 1.00. This always worked and the “cloth” would fall or fly away. I have three animations that I did this with quite some time ago. With the latest version of Blender (2.77a), it’s no longer working. Has this changed?

I figured it out. Using the “Vertex Weight Edit” modifier to remove vertices from the group, and keyframing the tick box.