This is partially fixed in the Beta. I'm still experiencing Steam Front navigation issues and oddly enough the fix for input scaling seems to have mostly fixed mod keys for the OSK with external controllers. The caps lock still doesn't work however.
Nothing extracted yet.
When navigating the store you'll find yourself in a situation where you need to use the joystick to navigate the OSK because the D pad no longer is recognized. Using an xbox one controller makes this a pain because the joystick moves the OSK in a very unreliable way (trying to move left will move it left + up etc).
Probably unrelated, but you will also find yourself in a situation where both up and down inputs will be registered as "Up" when scrolling through game lists or reviews until it reaches the top which then the down input is registered again.