I use two monitors, in an extended desktop, on my Mac (OS10.11.6), Firefox62.0 Firefox is my preferred browser. I often open several windows within Firefox -- as well as tabs within each window. I am seeking a keyboard shortcut that will change focus to another window, analogous to the cmd-Tab function in the MacOS (and alt-Tab in Windows world). The documentation lists several ways to change focus to particular tabs; but not windows. This became particularly irritating when I encountered a site recently that started spawning new windows -- by the time I stopped it, a dozen new (empty) windows were created. My only recourse in changing focus to the new window was to navigate the mouse to the Window menu, navigate down to each item in the list, click to change focus to that particular window, then cmd-W to close it. Rinse and Repeat, as they say. Is there any keyboard shortcut for moving focus to next window...or could I construct such a feature?