I have a native macOS Popover control in pure Xojo.
The problem I have with mine is custom controls (including the listbox) have the wrong cursor location. For canvases I can grab the current cursor location and therefore workaround it, but the listbox is urm… Just broken on a Popover. It’s almost easier to just build a custom control that has just what you need.
I have feedback reports from the days of 10.8, but they’re not a priority for Xojo. It’s something else I’d love to have the opportunity to fix (and get paid for it, I might add).