Hello, Richard
As Herr Völker already wrote, it wouldn't be very practical to remove the tray after each use. The parts for the tray arrive like this:
Once the tray has been bolted together it looks like this:
And the finished thing with transmitter looks like this:
However, you should be aware that the bolts which fix the tray to the transmitter replace the original bolts in the transmitter case. So were you to remove the tray each time, it would also mean that the bottom of the transmitter is no longer fastened to the top. I also had a compartment in my model's transport box for the old transmitter in which the new HS-12 no longer fits (neither with nor without tray). I now simply carry the transmitter in a separate aluminium case along with a few tools and bits and bobs.
I wonder, if Herr Völker is reading this, will Servonaut one day produce an aluminium transport case especially for the HS-12 with tray? I'm sure it'd be a great idea - especially if one could choose the panels (alu, or in the same colour as their HS-12)!
Hope this helps, Richard.
Greetings from Switzerland
Steve