For this thread (https://talk.remobjects.com/t/adding-custom-view-to-swift-macos-cocoa-project/16744) I know that it can not be used in embedded controls, but in windows, I usually build controls to use in my applications (Forms, WPF, aspx) that interact with the designer.
Is not there a way to build controls for iOS (XCode designer integrated) using Oxygene? Maybe not for controls embedded in an app but can not be built in a separate library?