I had a write-o, it's not typographical, as INS + Num Pad Slash is the desktop keystroke sequence while INS + Shift + M is the laptop sequence for bringing the mouse to the navigator object (that link, in this case), and that's what I was doing, not a left mouse click, which is just number pad slash for desktop.
I did not have luck with arrow down, at least not as consistently, after the hover over menus were visible. But hitting tab always took me through them, item by item. It appears that both methods work, so if down arrow didn't I'd try TAB or vice versa after having done the move mouse to navigator object command.
It is a PITA, but so much about using alternate access to what is a visual medium by design, is, and sometimes far more so than others. At least there appears to be a functional way to do it!
Brian - Windows 10 Home, 64-Bit, Version 1803, Build 17134
A little kindness from person to person is better than a vast love for all humankind.
~ Richard Dehmel