Not at all. Zen browser is trying to achieve Vivaldi UI on the Firefox browser - but more limited. Opera has been doing this for years... More fluid tab experi

Not at all. Zen browser is trying to achieve Vivaldi UI on the Firefox browser - but more limited. Opera has been doing this for years... More fluid tab experience looked nice - though I don't prefer vertical tabs, I liked that I could drag to make them bigger/compact, drag them to top/bottom/sides, and use a shortcut to HideUI. HideUI is the single most loved feature of this 'Firefox' for me. To get rid of the tab/tool/URL bars, but have access (via keyboard/mouseover) is awesome... though better if we could assign something like F7 tabs F4 toolbar.