Rebinding Inventory to an auxiliary mouse button will not close inventory as normal.

When inventory is bound to the keyboard, pressing the button twice will open and close the inventory, while when rebound to mouse button 4, pressing twice will only open the inventory. Esc has to be pressed to exit the inventory.

What I expected to happen was...:
Successful opening and closing of the inventory screen.

What actually happened was...:
The button opened the inventory screen, but subsequent presses did nothing.

Steps to Reproduce:
1. Bind inventory to mouse button 4
2. Exit the menu and press mouse button 4 twice