Here are the steps.
Go to system> administration > Synaptic Package manager
You will see following window.
Then select compiz-decorator and tick it and then apply it.
So now go to command line and type following command
Then you will see those buttons come back.
Then you need to add this to start up applications.To do that do followings.
Goto preferences > Startup Applications
You will see following window and type there as shown in the below image