WebView2 Dialog not loading

Hello everyone, I am trying to create better UI leveraging WebView 2 in my plugIn.
Currently, I have a panel that is rendering simple HTML. One of the buttons is supposed to open a dialog - also containing just a WebView. In the panel, I use many times described approach for communication in order to catch the event. Problem is, that after pressing the button, dialog opens but the WebView isn’t loading anything. On top of that, Rhino silently fails after couple of seconds.
When I try to open the dialog from regular Eto panel, everything works well.

Is there some limitation I should know about?