2015 Vista - Slide part fell off on floor

[wyocamper]

Yesterday when I retracted the driver side front slide a piece fell out on the floor. The Cortona parts list says it's a "Link-E Chain 50mm", but I can't really tell what it does. The other two slides don't have this part, and the slide seems to be working Ok. I'm going to call Winnebago and ask, but I thought I'd ask here first in case anyone else has seen this issue. And how to fix? The piece is one of the links in the yellow "chain" in the image.