Based on user feedback, we've removed the "Link behaviour when the page requests a new window" option under Settings > Link Opening, as this has been causing issues on some sites.
To replace it, there's a new option under Settings > Window Behaviour called "Opening new windows" which will allow you to pick between the App Matcher, New Window or Default Browser. This should be much more reliable.
This option doesn't port across automatically, there's more information available on the Knowledge Base (https://kb.wavebox.io/customise-new-window-handling/)