How do I use Unity drag handles?

The Unity multitouch grab handles plugin ships with Unity. It is activated by a three finger press on a touch screen. You can toggle it by repeatably tapping three fingers on your touchscreen.

You can use it with a mouse by toggling the plugin on and off. To ensure the plugin is enabled, do the following:

1. Start the CompizConfig Setting Manager: Press Alt + F2 to open the run dialog, type ccsm, and press Enter (if that doesn't work, you probably need to install the package compizconfig-settings-manager first).

2. The grab handle plugin will only work correctly, if the Png plugin is enabled, so scroll down to the Image Loading section and make sure Png is ticked:

   
   _{(source: xrmb2.net)}

3. Now scroll further down to the Uncategorized section and tick the Unity MT Grab Handles plugin:

   
   _{(source: xrmb2.net)}

4. By default, there is no shortcut defined to initiate the handles, so click on the Unity MT Grab Handles button to configure the shortcut (and also the fade duration, if you like):

   
   _{(source: xrmb2.net)}

5. Next to Toggle Handles click on the Disabled button and tick the Enable checkbox:

   
   _{(source: xrmb2.net)}

6. Now click on Grab key combination and press the desired shortcut:

   
   _{(source: xrmb2.net)}

7. Confirm and close the CompizConfig Setting Manager. Now you should see the handles like in the picture in the question when using the shortcut you just defined.