Assume that you're in a peer-to-peer (P2P) video call in Microsoft Skype for Business and that Citrix RealTime Optimization Pack 2.0 is running. When a remote user adds a third user to the call, the conversation window of the call becomes blue. Or, when you accept a second P2P video call, the video window that contains your own image becomes blue.
Note There may be other scenarios that also make the conversation window go blue. Several of these were solved by Citrix.
To fix this issue, install the February 9, 2016 update (KB3114732) for Lync 2013 (Skype for Business).
Note Lync 2013 was upgraded to Skype for Business in April 2015. Citrix RealTime Optimization Pack 2.0 requires the Skype for Business client.