If you drag-and-drop the backlinks pane into your main workspace, you can also do split right and/or split down from the right-click menu of the tab. Then you’ve got two backlinks pane, where you can search for various stuff.
And the pane remains linked to the active window, so if you change active document, the backlinks tabs will follow.
In the image below, I’ve done just this, and searches for Mac in one of them, and Mobil in the other. Then I dragged the tabs back into the side panes and now have two backlinks pane showing.