I was playing around with compizconfig. I don't remember what exactly I clicked. Since then, the close/minimize buttons and the sidebar vanished. I use 12.10 version. Please help me out.
Try (in terminal)
Let us know.
Please be aware of the issues you may be faced when running ccsm:
You most likely disabled the windows decoration in the "Effects" section like I did in the example below:
To re-enable them just tick this box and wait until Compiz restored the windows decorations.
In case we had opened the further settings of the Windows Decoration plugin we may need to restore them to defaults shown below:
To remove bad settings we may have made with ccsm we may also try to delete its configuration files in
Check if you have CompizConfig Settings Manager > Window Decoration enabled and check if CompizConfig Settings Manager > Window Decoration > Command has the default value