macOS NSOutlineView Source List Child Item Titles Disappearing

Hi everyone. I've implemented a Source List like NSOutlineView with Core Data entities that looks like this:



I'm happy with how it looks and works but I have a problem that I'm not sure how to correct. When the app loads the first child is automatically selected, which is fine, however; when I click on another child and then start selecting any other child above it, the titles for the previously selected children disappear:



I have implemented but all I do in there is gather some information about the child item that was selected.

Any ideas what is causing this and how I can correct it?

Solved

Not sure what was causing this but I've been able to resolve it by rebuilding the outline view in IB using an NSTableCellView and a label and image cell.