Our '06 just has a small rotating plastic latch held on by a screw. It looks like a small lever and rotates to the 3 o'clock position, to keep the door from opening. I only use it to keep the door secure while on the road. Otherwise we do not use it, much like Paula wrote above.
My guess is that it is was part number 702415-100 and then replaced by the more complicated part 381403.
It could well be that both were discontinued and replaced with the one pictured above because people tried to use them to keep the door closed while using the shower.
The magnetic strip will keep the door shut in-use so long as it is not leaned on. The door, hinge and frame are rather light and probably not designed to take much force leaning on them from the inside. If used that way, maybe it is better if the latch gives way rather than the glass or the door itself?
I love gadgets but some things are just better left simple.