I can't seem to find an answer for this, but when I'm in a call on Skype and I watch a video on Safari on iPhone, it automatically puts it on hold and when I've finished watching the video, it asks if I want to resume the Skype call which is good. However, sometimes it doesn't do that and when I watch a YouTube video on the YouTube app, it doesn't ask if I want to resume the call. When I'm done watching andI want to unhold it, I close the YouTube app and delete it from the processes thing (when you double press home button and end all open apps) but it still won't unhold the call. I have to end the call and then call again which can be annoying. I think there should be an unhold button.