Adjustable container holder for a vehicle door map pocket

A passenger door of a vehicle, comprising:

• a door panel a door panel including a map pocket having a container holder and a main body, wherein the main body defines an inner surface facing a passenger compartment of the vehicle, a lower end portion, and a shelf located at the lower end portion of the main body, wherein the shelf extends from the inner surface of the main body and towards the passenger compartment of the vehicle to define a portion of the map pocket;
• a door trim panel mounted to the door panel, wherein the door trim panel defines a remaining portion of the map pocket;
• a retention wall extending from the shelf of the main body, wherein the retention wall and a portion of the inner surface of the main body define the container holder;
• a living hinge connecting the retention wall to the door panel;
• and
• a retention member defining an elongated body having two end portions and a bowed section located between the two end portions, wherein the two end portions of the retention member are connected to the retention wall and the bowed section flexes towards the inner surface of the main body, and wherein the retention member is configured to elastically deform when a container is placed within the container holder.