UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10820.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3473.0 Safari/537.36
Platform: 10820.0.0 (Official Build) dev-channel gnawty

Steps to reproduce the problem:
1.set the shelf position on the left or right side 
2. do auto hide shelf 
3. click on the volume up/down/ mute 

What is the expected behavior?

What went wrong?
it should be more the right if the shelf is on the left, 
or should be more to the left if the shelf is on the right

Did this work before? N/A 

Chrome version: 69.0.3473.0  Channel: dev
OS Version: 10820.0.0
Flash Version: 30.0.0.127 /opt/google/chrome/pepper/libpepflashplayer.so

I hate the color and I think it should be more transparent to fit with the background image or the current tab