Ctrl-click or middle-click the Reload button to open the current page in a new tab.
   Ctrl-click or middle-click items in the history of the Back and Forward buttons to open a page from that list in a new tab.
   Duplicate a tab with its history by pressing CTRL and dragging the tab to a new position on the tab bar.
   Dragging a tab in the browser window will detach the tab and move it to a new window, this is called tab tearing.
   Drag a tab back to the tab bar in the original or anther window to undo a detach or move a tab to a specific window. If a window gets empty (you tear off the last tab) then that window will be closed automatically. "

Hello! https://support.mozilla.org/en-US/questions/762043 This solution should help you " Ctrl-click or middle-click the Reload button to open the current page in a new tab. Ctrl-click or middle-click items in the history of the Back and Forward buttons to open a page from that list in a new tab. Duplicate a tab with its history by pressing CTRL and dragging the tab to a new position on the tab bar. Dragging a tab in the browser window will detach the tab and move it to a new window, this is called tab tearing. Drag a tab back to the tab bar in the original or anther window to undo a detach or move a tab to a specific window. If a window gets empty (you tear off the last tab) then that window will be closed automatically. "