Hello,
Sorry to hear you are having issues. But, I can't reproduce your issue on my system. Here a screenshot

There might be something else is effecting your Vivaldi with Groupy. Check your extensions and if needed uninstall and reinstall might help.
And also.
Please try purge and reinstall Groupy steps as mentioned here: https://forums.stardock.com/488142/groupy-support-faq#reinstalling Just make sure to redownload the latest version from your account. Reboot after the purged. Reinstall, and Reboot again after the installation. Retest it. Report back here.
Thanks
Basj,
Stardock Community Assistant.