Microsoft doesn't provide developer's API for Skype 8.x. We use two usage scenario settings to prevent possible user interference of Skype calling status window to affect our gateway's decisions of call existence. The interference includes closing or hiding Skype call status window.
The first usage scenario setting is "Connect phone". This setting is most suitable for users in front of the computer when they use Skype gateway for a Skype call. Users can do whatever with the computer connecting with Skype gateway. But they need to put the phone hook-on by themselves when their call parties hang up first. Gateway device won't generate busy tone for such case. Users also need to make sure if the Skype call is finished or not when they hang up the call first and might need to manually finish the still in-progress call via Skype GUI. The second setting is" Connect with PBX". This setting assumes users won't interfere Skype call status window during a call. It is prohibited to close or hide Skype call status window during a call. If anyone controls the Skype call status window during a call, the call might be incidentally finished or call party might hear busy tone although the call is still in progress. And the call might not be finished automatically when user hangs up the phone. Users might need to manually finish the call via Skype GUI.