The documentation of the NSPopover property hasFullSizeContent says that when it's true, you should
Use the safeAreaLayoutGuide of the contentViewController view to ensure that your content is fully visible and doesn’t become clipped when displayed.
I can do that by adding auto-layout constraints programmatically, but is there a way to do it in the xib? When I googled it, the AI summary begins
To use safe areas in a Mac XIB (Interface Builder), enable the "Use Safe Area Layout Guides" checkbox in the File Inspector for your view
but I have not found any non-AI indications that such a checkbox exists for macOS.
(I'm using Xcode 26.2.)