"Add/Remove Hardware" icon
I think that you are speaking of the "Safely Remove Hardware" icon in the System Tray / Notification Area.
This is only present when there is a USB device plugged in.
If the device is not recognised it won't appear. If the USB device is connected to the docking station, it's possible that there's a poor connection between the device and the DS or the DS and the laptop.
It can frequently go AWOL, though, so your best bet is to google
"Safely Remove Hardware" icon missing and select the solutions that suit your circumstances.
SD