Have not solved it yet, but did discover I was using a version of my custom framework that was like 3 years old, so am updating the code to use it, but there are a lot of name changes to contend with
well I replaced tmy GUI framework with the latest version and the issue remains only that last added view is visible
well almost… seems the last FOUR now show
statusBar!.addToView(self) // self.contentView?.addSubview(statusBar!)
navigator!.addToView(self) // self.contentView?.addSubview(navigator!)
inspector!.addToView(self) // self.contentView?.addSubview(inspector!)
designer!.addToView(self) // self.contentView?.addSubview(designer!)
// the following are visible, but if I comment them out, some of above are then visible
toolbox!.addToView(self) // self.contentView?.addSubview(toolbox!)
vSplitter[0].addToView(self) // self.contentView?.addSubview(hSplitter)
vSplitter[1].addToView(self) // self.contentView?.addSubview(hSplitter)
hSplitter.addToView(self) // self.contentView?.addSubview(hSplitter)
```
seems something changed in recent macOS or Swift…. that now requires more use of CLIPTOBOUNDS, or at least adding a few of those solved the problem it seems