How to disable NSTextView in SwiftUI

Issue #702

The trick is to use an overlay

MessageTextView(text: $input.message)
    .overlay(obscure)

var obscure: AnyView {
    if store.pricingPlan.isPro {
        return EmptyView().erase()
    } else {
        return Color.black.opacity(0.01).erase()
    }
}