Images didn't get attached: https://imgur.com/a/v33iq https://imgur.com/a/hZAFr

@mib2berlin Hi, I thank you very much for your tip. This solves in great part my problem as my tabs are now represented by a simple text headline. This permits a clearer arrangement with much more tabs per page. The pop up windows in this configuration are still available, when passing over the tabs with the cursor. In the mean time I was studding an external solution, called 'Tab Outliner', with powerful tree functions. But I prefer the integrated display of tabs for starting to use Vivaldi. Thanks to your help I'm now convinced to leave Firefox as main browser.