Diagnosis
The Top Track silverware rack's support rails are made of a relatively flexible plastic. Over time, especially with heavy items placed in the center, they can permanently bend or sag. There's no adjustment or tightening mechanism.
How to Fix It
You need to replace the entire third rack assembly. The part number is usually W10878676 (confirm this matches your model's color). It's a simple swap: lift the old rack off its two glide rails on the door, and drop the new one in place. No tools required.
If That Didn't Work
If a new rack also sags quickly, you're likely overloading it. It's designed for lightweight flatware, utensils, and small kitchen tools, not heavy chef's knives or large measuring cups. Distribute weight to the sides.
Heads Up
To prolong the life of the new rack, avoid placing heavy items in the center. Load heavier items like spatulas or large spoons over the stronger side rails where they attach to the door glides.