Attempt to disable the focus ring

I try to diable the Focus/Ring status of some button on my SwiftUI project... but I fail !

The focus ring appeared with the Beta 7 and persist by default with the last revision.

I use the obvious modifier :

Button(action: {

withAnimation(.easeOut) {

self.hcal.toThisYearAndMonth()

}

}) {

Text("♢")

}

.focusable(false)

Any clues ?

Best Regards

Gerard