The more and more I have used Firefox and Thunderbird with extension such as MiniTrayR and then observed the behaviour of other apps that offer similar functionality, the more and more I have come to realise that tray icons make less and less sense with the Windows 10 taskbar paradigm - taskbar shortcuts on Windows 10 are the one and same buttons for launching as well as minimizing/restoring apps while also providing visual feedback of the running state (it is done through a small bar on the bottom of the task bar button that, when visible, indicates that the app is running) yet solutions such as that offered by MiniTrayR masks this visual feedback since the taskbar button's visual feedback suggests Firefox/Thunderbird is not running when the tray icon is active. I would love to see proper support for the Windows 10 taskbar paradigm by having the option to map the X (the window's close button) to the standard minimize function (i.e., to minimize to the taskbar on clicking X) and also to include an 'Exit Firefox/Thunderbird' pop-up menu item on the taskbar button and to then not use a tray icon at all. That way one maintains the correct visual feedback of the taskbar's button, indicating the app's status, for a consistent use-experience under Windows 10. I suspect this functionality may need to be part of Firefox/Thunderbird for Windows, but, if it is possible to have it as part of MinTrayR, then that's perfectly fine. Note that one could still retain the option to minimize to the tray including a new option to retain the correct visual feedback on the taskbar button while doing so. In fact, for the ultimate in flexibility, one would provide support for one of four possible states: close (close as normal), taskbar (close minimizes as per Windows 10 behaviour), tray (close minimizes to tray), or taskbar and tray (close minimizes both to the taskbar and the tray). Note that Viber Desktop for Windows closes to the tray while keeping the correct visual feedback for its taskbar button. Also, while I'm on the topic of minimizing: it should also be possible to start-up minimized and to have this be to the taskbar and/or the tray. Ideally Firefox/Thunderbird should simply respect Window's shortcut specification (it can be set to Normal, Minimized, or Maximized) and then Thunderbird, or via a extension such as MiniTrayR, have a setting to override the minimize state on start-up to minimize to the tray inclusively or exclusively of the taskbar button. This would cater for all possible start-up/close configurations and keep users happy. :)