The changes in WordPress 4.9 caused the custom color picker of Content Views Pro (which added the extra alpha/opacity channel to the default color picker) to be disappeared.
We released the Pro version 4.9.1 to resolve this compatible issue.
For Active License Owners
Please update Content Views Pro to the latest version (4.9.1 or above).
For Expired License Owners
Obviously, you can renew your license here to get the latest version which included this fix.
Or you can manually apply the fix by replacing the content of the file
color-picker.js in the folder
by content of this file Content Views Pro 4.9.1 color picker.