How to set up shape key driver in 2.80? So I have this character animation with a shape key that flattens and unflattens his hat:



(in glorious technicolor here)

It looks good. But the shape key is mucking up all my other Actions now. It is an omnipresent key. I heard that this can be fixed by keying a shape key driver instead of the shape key directly. So I set out to do this. Unfortunately, I hit a nasty bug where my driver says "Mute" as soon as it is created, and I don't know how to get around that. It is possible that I am not using the correct settings, but I was following the official documentation as closely as possible. When I try to set local rotation as the determining factor, I cannot get any result at all. When I try to do local translation as the determining factor, the shape key is "mute"ed from the moment his hat is scrunched (that is, it becomes instantly un-scrunched) to the moment his hat pops back up again (another pop-in transition); The shape key is being muted and it is preventing me from having any idea what I should be doing. Can anyone help me?

I made a painful recording of my struggle here.

IMPORTANT NOTE: This character is going to be exported into Unity so I can't use modifiers that will not export to FBX.
The problem was that I was setting a driver for the MUTE property of the shape key, not the VALUE property. In order to set a driver for the VALUE, right click the value and you will see an option to add a driver.

I was convinced yesterday that it was not possible to right-click the VALUE (as of 2.80) and see an option to add a driver, that I had to right-click the checkbox instead. This was a mistake. Thank you to everyone (@Edgel3D) who tried to help. The problem is now solved.