If you want to share your screen into HighFidelity you can use this WebRTC application:
Open this link in a Chrome Browser, install the requested plugin,
type an unique name and click the “Share Your Screen” button.
Right click on “Share this link”, copy link address and paste it in Web Entity on Source URL
* If you don’t see the Share this link, because of the resolution, you can use Ctrl - to zoom out the content,
or just copy the new generated link address from the browser URL.