I am sure I hit some button or command by mistake. now when I'm trying to move a single vertex from object, it de-shapes the object instead of moving vertex and faces around it. here is the screenshot
Arrow is showing the pixel that I am moving. object is a simple cylinder divided from center.
O? This will enable/disable Proportional Editing – J Sargent Mar 25 '15 at 17:07Mesh>Proportional Editing– Mar 25 '15 at 17:16