You would require a GUI on Ubuntu container to run IB-Gateway and connect your client to it. Try installing VNC server on the container and then connect to it from your host (windows) machine. It should work. You can refer to on the how part.
Or, you can skip all the steps of installing a browser, VNC server and so on, and use image. All you need to do is to connect to it, install IB-Gateway and connect your client. I have used it with TWS and it works like a charm.
