Problem in unordered list

Hi, I don’t know if its the right section but please moved it if its not.

[ Moderator note: moved to Fixing WordPress. ]

.
I try to replace default style for unordered list. I put image as my
style for unordered list. I am successful in replacing the default style list but when I hover the first list on an unordered list, the image style is disappearing.
.
The weird thing is that the other list on the same unordered list are fine. Only the first list is affected. I checked the css but there is no list:hover whatsoever style on it.
.
Anyone experiencing this?