NStableView inside a NSpopover doesn't read VoiceOver keyboard navigation hints

My app has an NSpopover and its contentView's hierarchy is as follow, but when voice over is on, it will only announce "You are on a cell".

I want VoiceOVer read keyboard navigation hints ( like this picture).:

Setting the NSPopover's window's accessibilityRole to windows will make VO read the hints, but not work on Catalina and versions before

NStableView inside a NSpopover doesn't read VoiceOver keyboard navigation hints
 
 
Q