I am having a strange issue with a checkbox on an ipad app that i have been given to fix. The only way i can check it is if i click slightly outside of the checkbox. i can remove the css stylesheets and the problem still occurs. The html5 code validates. When i removed the jquery import the problem went away. i tried updating jquery to the latest version but still no good. It may be something to do with jquery UI, which is also being used. However, i cannot remove this as the app doesn't display if i do. 

Does anybody have any ideas? Things i can check/try? 

Thanks.