clipped from: addons.mozilla.org 
Open panel to left, bottom or right (left,middle or right click) with current URL from Split on context menu (right click on page) of the tab's page.
Open panel to left, bottom or right (left,middle or right click) with current URL from Split on context menu (right click on page) of the tab's page. Allows you to view see two pages simultaneously for comparison or copying info from one to the other. Can be resized by dragging the bar between the main browser and new panel.
