Have you tried changing the cap? I exclusively use the concave "soft rim" cap (http://support.lenovo.com/ContentResources/Migrated%20Assets/pc/support/site_wss/

Have you tried changing the cap? I exclusively use the concave "soft rim" cap (http://support.lenovo.com/ContentResources/Migrated%20Assets/pc/support/site_wss/14288_softrim.jpg http://support.lenovo.com/ContentResources/Migrated%20Assets...).