How To Enable ‘Minimise On Click’ in Ubuntu 15.10
Ubuntu 15.10 comes with “minimise on click” Unity feature which allow app windows to be minimised by clicking on its respective icon in the Unity Launcher. It will function just like a Window OS click launcher and the app windows can be restored once user re-click on the app icon.
The Minimize on click in Ubuntu 15.10 is not enabled by default and you will have to enable it using CCSM (CompizConfig Settings Manager).
sudo apt-get install compizconfig-settings-manager
You can also install it via Ubuntu Software Center.
Once installed, go to Dash and type CCM and open CompizConfig Settings Manager.
Under Compizconfig Settings Manager, click Ubuntu Unity Plugin and under the Launcher tab, tick the option “Minimize Single Window Applications (Unsupported).”