Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
The issue is in the title When I open a private window and vivaldi is not default browser, it asks to become default one. I'm on a mac, FYI.
I don't expect that a private window would ask to be a default browser, moreover when I opened current window browser already asked that question.
Looks like your connection to Vivaldi Forum was lost, please wait while we try to reconnect.