After installing Pantheon on ubuntu 15.10, there is a missing icon in Wingpanel. Only the volume and network icons are visible.
How should I proceed in attempting to fix this missing icon?
Try the following. I had the same problem and this worked for me:
sudo add-apt-repository ppa:elementary-os/daily
sudo add-apt-repository ppa:elementary-os/os-patches
sudo add-apt-repository ppa:elementary-os/testing
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install elementary-theme elementary-icon-theme elementary-default-settings elementary-desktop