#primary div disabling #secondary div in Chrome

[drcula112]

I have a weird bug in Chrome which affects a page in Wordpress.I am using a slightly modified Wordpress Twenty Eleven child theme. The only modification are basically CSS only, and it only contains colors / sizes mostly.My problem however is that if I insert the category list widget then the whole #secondary div becames non-clickable, until the #primary div is covering vertically. It only happens in Chrome, Firefox is OK.Can you have a look and tell me what is wrong? I think there is nothing wrong with the child theme and yet, this bug is quite serious. Is it a Webkit related bug, do you think, or just something wrong with the HTML/CSS?Live site