Wacom Intuos Pro Manual page 54

Express View
You can enable Express View to see the current settings for your ExpressKeys at any time.
Check the Show Express View checkbox on the ExpressKeys tab.
Lightly touch any ExpressKey to view the current ExpressKeys settings on your screen.
The display will fade out after 2 seconds on the screen.
To disable the display, uncheck the Show Express View box.
Important: Some applications can override and control the ExpressKey functions.
The above screenshot is for descriptive purposes; it may not match your screen.