System tray menu acts weird

We can improve the system tray menu by several ways. Few strange behaviors happen on GNU/Linux & Mac, perhaps sometines on Windows:

1.
First clic on the icon: it opens the menu.
Second click does nothing.
=> It should close the menu.

2.
First clic on the icon: it opens the menu.
Second click not inside the menu does nothing.
=> It should close the menu.

There are few improvements into the code we can do too.