why the enableRowsHover is useless?

Suite and Optimus Suite 5
#1

i use the follow code ,the hover background color is no changed

[code]
.hover {
background-color: red;
}

[/code]

but use overwrite rowselected can do it.

<style> .rowselected{ background-color: red; } </style>
some body can tell me what wrong with my first code?

#2

i am sorry ,it caused cache in brower, it is normal now