Back shortcut (the cmd+[ and cmd+]) only works when History menu is open, on MacBook Pro, and not when History menu is closed, same for forward. I have my Logitech mouse set in such a way that the back button sends a keystroke equivalent of cmd+[. When I press the back button on my mouse, the History menu item highlights blue as if shortcut has been accepted but nothing happens. If I open History menu item with my mouse's left click and then press the back button, the back action happens and previous page loads and History menu closes. Of course I could press cmd+left/right arrow (which works) but I couldn't use back with my mouse then. I have the cmd+[ shortcut set because it is system wide shortcut whereas cmd+left arrow sometimes performs different action or none at all (it has no effect in Finder for example). So the expected result is that the cmd+[ shortcut actually performs action and doesn't just give visual feedback without action.