Minimize On Click, the long awaited feature is now available in Ubuntu 14.04 Trusty Tahr and it is disabled by default. You can enable it from Compiz Settings Manager, but first you need to install CompizConfig Settings Manager.
When Minimize On Click is enabled, rather than an open application minimizing when its launcher icon is clicked, Unity focuses the window. In scenarios where you have more than one window opened, it triggers the App Spread allowing you to choose from which running window or app desired.
Video Click of Minimize On Click in action by Quidsup
sudo apt-get install compizconfig-settings-manager
– Launch Compizconfig settings manager from dash > click on Ubuntu Unity Plugin under Desktop
– Click on Launcher Tab > Scroll down and enable ‘Minimize Single Windows Applications (Unsupported)’
– Logout and login again.