Button with PlainButtonStyle doesn't get tapped when the window is inactive

I'm writing a MacOS app. I'm displaying a button. When the app is inactive, if I click the button, the button's tap event gets triggered as the same time as the window is activated. So far so good.

However if I now add .buttonStyle(PlainButtonStyle()) to my button which is the desired look, it doesn't get tapped when the window is inactive. The first click activates the window and I need a second click to trigger the button.

Button {
  print("tapped!")
} label: {
  Image(systemName: "doc.on.doc")
    .resizable()
    .frame(width: 14, height: 14)
    .padding(5)
}
.buttonStyle(PlainButtonStyle())

Whether a view can receive the click event without their window being activated is controlled by the acceptsFirstMouse(for:) method. When the button style is .plain, the button is no longer backed by an NSButton (whose acceptsFirstMouse method would have returned true), so you can no longer "click-through" the button.

You can wrap a NSViewRepresentable around the button, and override acceptsFirstMouse to return true.

This is the code from this blog post

extension SwiftUI.View {
    public func acceptClickThrough() -> some View {
        ClickThroughBackdrop(self)
    }
}

fileprivate struct ClickThroughBackdrop<Content: SwiftUI.View>: NSViewRepresentable {
    final class Backdrop: NSHostingView<Content> {
        override func acceptsFirstMouse(for event: NSEvent?) -> Bool {
            return true
        }
    }

    let content: Content

    init(_ content: Content) {
        self.content = content
    }

    func makeNSView(context: Context) -> Backdrop {
        let backdrop = Backdrop(rootView: content)
        backdrop.translatesAutoresizingMaskIntoConstraints = false
        return backdrop
    }

    func updateNSView(_ nsView: Backdrop, context: Context) {
        nsView.rootView = content
    }
}

Example usage:

Button("Foo") {
    print("triggered")
}
.buttonStyle(.plain)
.acceptClickThrough()