top layer doesnt floats

Hi,

You can see on my script http://www.phpsunchat.com/chat/ if you move your mouse over username after registering in online userlist the quick profile doesnt float above the most popular chat rooms div. What is the reason.

I tried the method fixed, absolute and relative it didnt solved my problem.

Screenshot of the problem : https://gyazo.com/8592cf7db495facb45879619a7ec6935

Can anyone help!