Remove ButtonGroup.addButton()

Since the application should use RadioButton.setGroup() to add buttons to a group rather than invoking ButtonGroup.addButton(),
will you consider to remove ButtonGroup.addButton()?

Just because application developers should use RadioButton.setGroup() does not mean that addButton() is useless, see the source. Also, visibility cannot be reduced because the classes reside in different packages.

I'm refreshing this thread,

I'm refreshing this thread, since I was surprised with RadioButton.setGroup(). Using only ButtonGroup.addButton() doesn't work actually, you have to use RadioButton.setGroup(). On the other hand if echo2 wants to be similar to Swing, then RadioButton.setGroup() should be removed (well it can't be really removed at this point). In Swing a RadioButton can be a member of a few groups which can be useful sometimes, but in this case a method like RadioButton.setGroup() shouldn't be used at all.