Binding open shop to scroll wheel doesn't work when trying to close it

[Fergus Bentley]

Say you bind open shop to scroll wheel down. You can use it to open the shop but not to close it. With most keys you can press it again to close the shop but in this case you have to use Esc to close it. Now why would you bind open shop to scroll wheel? Good question. But it's a bug, so I'm reporting it.