I have a MapControl with an associated TOCControl as a buddy.
Working with the underlying map, I can add a group layer programmatically. The group layer shows up properly in the TOC.
Later I programmatically add child groups underneath the group layer as well as feature layers. When control returns back to the viewer, the features are rendered on the MapControl, but the original group layer is unchanged, as if there were no child layers. I can interactively change the visibility of the group layer which hides/shows the underlying feature layers, but I can't actually get to them.
If the layers are added to the map prior to displaying the controls, the layers show up properly in the TOC.
I've tried the refresh method on both the map and TOC controls.
[UPDATE: Definitely an issue with groups. If I add multiple group layers to the map itself, they show up in the TOC. Layers under the group do not show in the TOC.]