Where does water in shower plumbing go after a shower?

I’m trying to debug some funny sounds in my shower (just purchased the house containing the shower) and would like to better understand how the plumbing works. The shower is a stand-in type with no tub.

I can visibly trace cold and hot water pipes into my shower ceiling and then down into the wall containing the shower valve. The cold and hot pipes enter the shower valve fitting (which is four feet from the floor). From there, I assume opening the shower valve lets water flow up into the pipe that supplies the shower head (which is 6.5 feet from the floor).
This is my question. When I shut off the shower valve, there must still be about 2.5 feet of pipe (this is the pipe that joins the shower valve to the shower head) containing water. Does that water remain there until the next opening of the valve forces new water into the pipe pushing the old water out through the shower head?

Is there some sort of relief valve that drains that pipe of the water?

Background – After a shower, for about three minutes, I can hear drops somewhere in the wall that contains the shower valve and I am trying to find the source. I’ve opened up the wall behind the shower and all pipes and fittings are dry.

EDIT: The source of noise was my Culligan filter shower head. I removed the shower head and the noise disappeared. Thanks to all for the ideas.