Product review (3 stars): After two failures!
This is the right part to replace and , unfortunately , emulate yet another defective design by WP. The end flange extensions are not thick enough to carry the drawer weights when loaded. What I did was purchase a piece of aluminum flat bar at one sixteenth inch thick and epoxy it to the top flange to thicken up and strengthen the support. There is just enough space in the cutout for the support to accommodate the bar thickness without making the shelf sit wrong. I have had this repair in for months now and it is holding fine. The broken extension is staying bonded to the aluminum.

Thanks again Whirlpool for making our lives a little harder.