ubuntu sidebar solution

Steps to repair ubuntu sidebar  

 Open a terminal with Ctrl+Alt+T.

You can also open terminal by right click 

sodo install compizconfig-settings-manager 

sudo apt-get install compizconfig-settings-manager

after this run :-

1. DISPLAY=:0 ccsm &
2. The first part tells the terminal which display you want it to load on (otherwise it won’t have a clue).

Now press Ctrl + Alt +F7 or F8

There should be a CompizConfig Settings Manager.

Find the Unity plugin and  enable it. You will be asked Ubuntu Unity Plugin requires the plugin OpenGL. 

Enable Ubuntu Unity Plugin / Enable OpenGL

now you need to restart your PC on  terminal run sudo reboot.

Done...