My plan for my next electron app is to use one of 98.css [1], XP.css [2] or 7.css [3], so I can have proper native-looking app.
[1] https://jdan.github.io/98.css/
[1] https://jdan.github.io/98.css/
Interestingly, the 7.css fixes this by showing them as expander links instead.