The Touch Bar on the new MacBook Pro is like Mary's little lamb. Wherever you go, it is sure to follow, changing the buttons and controls it offers as you change apps. If you encounter a problem where the Touch Bar becomes unresponsive, there are a couple ways you can refresh it. Plus, there's a way to refresh just the Control Strip portion of the Touch Bar.
But first, Force Quit
Before resorting to refreshing the Touch Bar, you might try quitting the app upon which the Touch Bar is stuck. If the app itself is unresponsive, then you'll need to force quit it. To do so, click the Apple button in the upper-left corner and choose Force Quit. From the Force Quit window, find the app that's giving you problems and click the Force Quit button.
Refresh the Touch Bar via Activity Monitor
To refresh the Touch Bar, launch the Activity Monitor and search for the Touch Bar agent. Click on the Touch Bar agent line to select it, and then click X button in the upper-left corner and click Quit.
Refresh the Touch Bar via Terminal
You can also use a Terminal command to refresh the Touch Bar. Launch Terminal and type in the command pkill "Touch Bar agent" and hit Return.
Refresh only the Control Strip
The Control Strip is the rightmost portion of the Touch Bar that features buttons for screen brightness, volume and Siri. If it becomes stuck or shows a blank space where a button should be, you can use a Terminal command to refresh just this portion of the Touch Bar. Launch Terminal and enter the command killall ControlStrip and hit Return.
In related news, learn how to put your favorite controls in the Touch Bar and get 7 Touch Bar tips and tricks.