I made a custom browser entry for Vivaldi Browser.
However, when choosing Vivaldi (with or without an incoming URL), I get "The target browser does not exist in the target location."
Browser: Custom
Display Name: Vivaldi
Target: C:\Program Files\Vivaldi\Application\vivaldi.exe
Image: Custom
Custom Image: C:\Program Files\Vivaldi\Application\IDR_MAINFRAME.ico
Urls: [blank]