Yup there should be an option in your browser options to "clear cookies and other plug in data" when you close your browser - exact wording will depend which browser you use.
If that is ticked it might improve your meter slightly but it will delete all your WGT preferences every time you close your browser.
As for the putting grid, I think it has always disappeared when you start to take your shot.
EDIT. Sorry YJ is right - you can force the grid to stay on from the options menu until you actually strike the ball.