How to use the buttons from Selection UI (DOORS NG)?

I am trying to create a tool interaction between DOORS NG and my created consumer application via OSLC. I managed to work my way up to Selection UI, but unfortunately at this point I don't know how to go on. If I put the Selection UI into an iframe or call it up in the browser, then I cannot perform any action with the offered buttons. That means, nothing happens, neither if I press OK nor CANCEL, at least nothing visible happens.

I've been wondering if I have to activate the buttons tool-sided at DOORS NG and if they really don't have a function yet or if I have to provide a kind of event listener that listens to possible messages from the button/iframe.

Can anyone help me out here? Is there anything I missed?

Thanks in advance.