bordered NSButton doesn't switch between icon and alternate icon on click?

[Sebastian Reitenbach]

Hi,

I mocked up this little test app here: [1] with two buttons, one bordered, 
I've a button with just icon, and alternate icon on it. When I in Gorm disable 
the Bordered option, then
the button doesn't alternate between the icons anymore. Have seen that at least 
with "PushOn/PushOff"
and one more, I believe it was the NSMomentaryPushButton.
With Bordered option enabled, it alternates on click.

Just checking if this is a bug, or I'm missing something?

thanks,
Sebastian

[1] https://github.com/buzzdeee/TestBorderedButton