[applet] Give FullRepresentation an implicit size
Otherwise the popup is tiny when using the applet on the desktop or on a panel directly (not in the system tray)
24 grid units was chosen because that's the system tray popup size
Otherwise the popup is tiny when using the applet on the desktop or on a panel directly (not in the system tray)
24 grid units was chosen because that's the system tray popup size