When scrolling the mouse and back up at the same time, some inventories switch positions.

What I expected to happen was...:
Nothing

What actually happened was...:
When scrolling the mouse and back up at the same time, inventories often (not always) switch positions.

Example: I have the bow in position 9 and position 3 is active. Position 6 may switch position with inventories at the first row and the active position is randomly set. This is frustrating especially when attacked by monsters.

Steps to Reproduce:
1. Move forward
2. Move backward and at the same time scroll the mouse to switch active position in the inventory
3. Often, inventories switch positions.