Sorry if that has been answered before but couldn't find it in the forum...
I can overwrite the getComboBoxFont method to change the font size of the selected item, but apparently that does not change the size of the items in the drop list. I tried changing idealHeight in the getIdealPopupMenuItemSize method but that didn't work etiher.
I know. The question in fact was: "which method should I override?"
I eventually overrode both getIdealPopupMenuItemSize (idealHeight) and drawPopupMenuItem (font.setHeight) and it works. But I am not sure it is the right way...