Window List is a small application indicator which displays a list of open windows on the top Unity panel. The windows can be activated by selecting them from the indicator drop-down list.
To install Window List indicator in Ubuntu 12.10, 12.04, 11.10 or 11.04, use the following commands in a terminal:
sudo add-apt-repository ppa:jwigley/window-list sudo apt-get update sudo apt-get install window-list
Once installed, run "Window-List" from Dash.
From the Window List indicator menu, you can configure a couple of settings: you can choose if Window List should display window icons or not and if it should run at startup:
Thanks to fossfreedom for the tip / info via AskUbuntu.