Hi, I'm experiencing a problem with the WebDropDown. When I hover it, the image of the arrow gets lost. Is there something wrong with the css file?

Here's the css file:

/*

Main control CSS class
*/
.igdd_Control
{
color: #444444;
}

/*
Main Control CSS class when it's disabled
*/
.igdd_ControlDisabled
{
}

/*
Main control css class on hover
*/
.igdd_ControlHover,
.igdd_ControlArea.igdd_ControlHover
{
background-color:White;
border-color: #666666;
}

/*

*/
.igdd_ControlFocus
{
border:solid 1px #C9C9C9;
table-layout: fixed;
background: none;
}

.igdd_ControlArea
{
border:solid 1px #C9C9C9;
table-layout: fixed;
background: none;
}

/*
CSS class for the actual input field (<input type="text" />)
*/
.igdd_ValueDisplay
{
background-color:transparent;
font-weight:normal;
font-size:10pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
border-width:0px;
width: 100%;
z-index: 0;
}
.igdd_ValueDisplay::-ms-clear
{
display: none;
}

/*

*/
.igdd_ValueDisplayHover
{
background-color:transparent;
}

/*

*/
.igdd_ValueDisplayFocus
{
background-color:transparent;
}

/*

*/
.igdd_ValueDisplayDisabled
{
background-color:Transparent;
border:0px;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
font-size:10pt;
font-weight:normal;
width:100%;
z-index:0;
}

/*

*/
.igdd_ValueDisplayReadOnly
{
}

/*

*/
.igdd_DropDownList
{
background-color:White;
font-size:10pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
margin:0px;
padding:1px;
}

/*

*/
.igdd_DropDownListHover
{
}

/*

*/
.igdd_DropDownListReadOnly
{
}

/*

*/
.igdd_DropDownListContainer
{
background-color:White;
border:solid 1px #868686;
float: left;
}

/*

*/
.igdd_DropDownListContainerHover
{
}

/*

*/
.igdd_DropDownButton
{
width: 22px;
height: 22px;
z-index: 9999;
}

.igdd_DropDownButton img
{
display:block;
}

/*

*/
.igdd_DropDownButtonHover
{
}

/*
CSS class that controls the style of the LI items in the list
*/
.igdd_ListItem
{
font-size:10pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
border:solid 1px White;
padding:3px 5px 3px 5px;
list-style-type: none;
width: auto;
min-height: 15px;
height: auto !important;
cursor:pointer;

color:#1F3979;
}
/* IE 6 fix */
.ie6 .igdd_tListItem {
border:solid 1px white;
}

/*

*/
.igdd_ListItemActive
{
background-color:White;
border:solid 1px #3AB5E9;
list-style-type: none;
}

/*

*/
.igdd_ListItemHover
{
background-color:#CCCCCC;
background-repeat:repeat-x;
background-position:0px -92px;
background-image: none;
border:solid 1px #999999;
list-style-type: none;
}
/* IE 6 fix */
.ie6 .igdd_ListItemHover {
border:solid 1px white;
}

.igdd_ListItemSelected
{
background-color: #9ECBD6;
background-repeat:repeat-x;
background-position:0px 0px;
background-image: none;
border:solid 1px #4897AA;
list-style-type: none;
}

/*

*/
.igdd_ListItemDisabled
{
list-style-type: none;
width: auto;
cursor:default;
}

/*
Applied to the whole pager
*/
.igdd_Pager
{
background-color:Transparent;
border-top:solid 1px #868686;
vertical-align:middle;
}

/*
Loading message container
*/
.igdd_LoadingItemsMessage
{
background-color:#4897AA;
font-weight:bold;
font-size:10pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
margin:1px 0px 0px 1px;
padding:3px;
color:White;
width:80%;
}

/*
Styles the current page link only
*/
.igdd_PageCurrent
{
font-size:8pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
margin:5px 3px;
float: left;
cursor:pointer;
color:#37ADDF;
text-decoration:underline;
vertical-align:middle;
}

/*
Styles all page links in general
*/
.igdd_PageLink
{
font-size:8pt;
font-family: Segoe UI,Verdana,Helvetica,sans-serif;
margin-top:5px;
margin-right:3px;
float: left;
cursor:pointer;
color:#484848;
vertical-align:middle;
}

/*
pseudo class used so Value Display input does not have focus
glow in some browsers like GoogleChrome or AppleSafari
*/
input:focus
{
outline: none;
}

/*.igdd_ListItemActive a:link
{
color:#484848;
text-decoration:none;
}*/

.igdd_ListItem a:active
{
}

/*
Styling for anchor when hovered anywhere on ListItem
*/
/*.igdd_ListItemHover a:link
{
color:#484848;
text-decoration:none;
}*/

/*

*/
.igdd_ListItemFocus
{
list-style-type: none;
width: auto;
}

/*

*/
.igdd_DropDownButtonFocus
{
}

.igdd_ListItem a, .igdd_ListItemSelected a
{
color:#444444;
text-decoration:none;
}

.igdd_ListItemHover a {
color:#444444;
}

.igdd_ListItemSelected a
{
color:#444444;
}

.igdd_DropDownListContainerFocus
{
}

/*.igdd_ListItem a:hover
{
color:White;
}*/

/*
For Disabled=True of a DropDownItem
*/
.igdd_ListItemDisabled a:link
{
cursor:default;
color:#8D8D8D;
}

/*
CSS class for the table that accomodates the value display and the drop down button, and which is a
child of the main control (div)
*/
.igdd_ValueDisplayTable
{
}

/*

*/
.igdd_DropDownButtonDisabled
{
}

/*

*/
.igdd_DropDownListFocus
{
}

/*

*/
.igdd_DropDownListDisabled
{
}

/* hide IE 10 clear button */
.igdd_ValueDisplay::-ms-clear
{
display : none;
}