Hi 3rdAveSlinger, Very odd. There is bug report for this problem, so it will hopefully be resolved soon: https://bugzilla.mozilla.org/show_bug.cgi?id=1108802 In the meantime, until it's fixed you might find Firefox's tab groups a useful alternative: [[Use Tab Groups to organize a lot of tabs]] Alternatively, you might be able to switch between Firefox windows by right-clicking the Firefox icon on your dock, or by prssing Cmd+` on your keyboard. (Cmd is the key that has a ⌘ symbol) Hope this helps, Jayelbe