Reported in the support forum - https://support.mozilla.org/en-US/questions/1048943 If you use the command+` system shortcut for cycling though windows and at any time hit only ` the direction you cycle though the windows will reverse. This behavior only happens in Firefox and no other OS X applications. STR: 1. Open 3 or more windows in Firefox 2. Use command+` to cycle though windows. Note the order the windows appear. 3. After completing one cycle, press ` only. 4. Now cycle though windows using command+` - notice the the order of the windows has reversed. 5. Repeat this process with another OS X app and notice that the order of the windows does not reverse in step 4.
I'd like to look into fixing this myself. I'll seek out some mentoring.
I see the described reversal behavior in Firefox, but Safari and Chrome also do the same thing (make sure you're not typing in the URL bar when you hit just `). I don't think there's a bug here.