Pop Out Dialpad disappearing on desktop when I answer

I am using the Poly Voyager 6200 UC, when the phone rings it rings on my phone and desktop apps at the same time. When I am a backup to the receptionist and a phone comes through, when I answer using my headset it goes to my mobile app and the pop out dialpad disappears on the desktop app. When a call comes straight to my extension or is transferred to me, when I answer from my headset the pop out dialpad on the desktop app stays there. I need the pop out dialpad on the desktop to be there so I can transfer calls. How do I stop it from going away?