Grid header checkbox is not aligned properly

[rishu27]

I have a gridpanel with checkbox column but after upgrade to Extjs 4.2 , checkbox header is not aligned properly. Please take a look of image attached with this post.44490

[slemmon]

Does it look ok for you here (looks ok to me):
http://docs.sencha.com/extjs/4.2.0/extjs-build/examples/grid/grid-plugins.html?theme=classic

When you upgraded to 4.2.0 did you link to the CSS resource from the 4.2.0 SDK as well as the JS lib file? Are you running any of your own CSS that might interfere with the CSS from the SDK? What browser are you seeing the issue? If it's IE is it running in compatibility mode when you see the issue?