Further information
I just updated LWJGL to 2.8.5 and the shift key still becomes stuck every time I press it. The weird thing is that pressing F11 fixes it temporarily (till Shift is pressed again).

So I assume this is not a bug in LWJGL!

If a mod thinks it is the fault of LWJGL anyway, explain why you think so.

Beeing able to rebind the hotbar keys (1-9) and the shift-inventory-key (which is also used for crouch by default) would help a lot for users of different layouts.

What I expected to happen was...:
Shift not getting stuck when you use it for inventory management or crouching.

What actually happened was...:
Shift becomes stuck after pressing it once. (Even if I use another key for crouching.)

Steps to Reproduce:
1. Use, for example (I've heard it also happens for others), the NEO-layout on a linux-distribution. (NEO-Layout on Windows works though.)
2. Press Shift.
3. Try to move an item in your inventory with your mouse.