The drawer has a secret compartment at the back.
A thin piece of cherry the length of the side (minus 1/2″ for clearance) is glued and screwed to a block of wood at the back of the case. On the end of this ‘spring’ is glued a shallow wedge that is thick enough at the widest end to just catch the on the front of the divider and prevent the draw from being removed.
When the draw is slid out the wedge, held in place by the ‘spring’, catches on the front of the secret compartment.
The wedge can be lifted with the finger and the draw slid all the way out. The back of the draw is chamfered so that when the draw is slid back in place the wedge rides up over the back and falls back into place.
I added a small divider to allow the wedge to slide across the compartment gap.