Changing Toolbar Font Size causes menu popups to inherit font size

Is this by design? Can this behavior be changed so that, buttons/menus/labels use the toolbar font size, but the submenus themselves do not inherit this font size?

Reason being is, I prefer the font size on my toolbar to be 10pt font, but this is too small for the popup menus.

Yes, it is by design.

There isn't currently a way to specify separate fonts for the same toolbar's top-level and sub-menus.