TAB-function SMP

What I expected to happen was...:
Showing the player list

What actually happened was...:
It does not show the player list if you keep 'a' and 'shift' pressed. It does not shift if you keep 'a' and 'tab' pressed, and you cant walk left if you have 'tab' and 'shift' pressed.

Steps to Reproduce:
1. Press any key combination of 'a' 'tab' and 'shift'. The last key you press will not work.