I am using Skype 22.214.171.124 on Ubuntu 12.04.
When someone and I were talking on Skype, he accidentally ended the call. When he called back to me, there is a window similar to the following (except mine is waiting me to answer the call, while the image below is already talking over the phone. the image is not mine but borrowed from somewhere on the internet. I couldn't screenshot the window in time). In the window, I can't find a button to answer the call, and only find buttons that to end the call etc:
So how do I pick up a call in such a case?