Tab Scope shows a popup when mouseover on a tab. You can see the real-time preview of the tab contents and navigate (Back / Forward / Reload / Stop) through the popup.
Click the glass icon or right-click on a preview to toggle two preview sizes, which can be configured with [Options].
Wheeling mouse on a preview to scroll the page or frame.

Tab Scope also shows a popup when mouseover a menu item in the [List all tabs] popup.

You can directly click links and buttons inside of a preview.

If you place the tab bar at the bottom of the window, you should set [Alignment of Popup] to [on top of a tab].

If you are using an extension which enables to display tabs vertically, you should set [Alignment of Popup] to [on the right side of a tab].