LAMW - how do I change the color of the (overflow) menu?

[Manlio]

jToolbar contains a menu, and when the items in the menu don't fit, they "overflow", i.e. a three-dot icon appears on the right, and when you tap it, the remaining menu items  are displayed in a sort of popup menu, aligned to the right.

Now, this popup menu's colors are black text on white background, and I would like to programmatically change them to white text over black background when my app goes into "dark mode".

I can change the color of the jToolbar, but that doesn't seem to have any relation to the color of the overflow menu.

Can anyone help? How do I access the overflow menu object? What class is it? How do I change its BackgroundColor and FontColor?

Thanks and kind regards