You can now control a hopper with redstone (to stop in- or output of items), nice feature.

But a lever placed on top of the hopper don't work.
And you can't place any levers at the sides of the hopper.

The redstone only works from a block from the side (see attachment)

edit:
the fix (lever on top can top the hopper) had the side effect:

Weighter Pressureplate