No, it does not happen on http://www.zencart137.jadetrue.com

Here is my CSS, must be something wrong with it?

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body {
behavior: url(includes/csshover.htc);
}

/*green*/
div#dropMenu li a:hover, div#dropMenu li.submenu li.submenu:hover {color: #4f4f4f!important;background:#ffc708;}


/*blue
div#dropMenu li a:hover, div#dropMenu li.submenu li.submenu:hover, div#dropMenu ul.level2 a:hover {color: #ffffff!important;background:#6C99D9;}
*/

/*red
div#dropMenu li a:hover, div#dropMenu li.submenu li.submenu:hover, div#dropMenu ul.level2 a:hover {color: #ffffff!important;background:#DC262E;}
*/

/*grey
div#dropMenu li a:hover, div#dropMenu li.submenu li.submenu:hover, div#dropMenu ul.level2 a:hover {color: #4f4f4f!important;background:#D5D5D5;}
*/
#buttonmenu {
width: 815px;
height: 25px;
margin-bottom: -6px;
margin-left: auto;
margin-right: auto;
position: relative;
top: -100px;
}

div#dropMenu {
width:70em;
margin:0 auto;
text-align:center;
z-index:1000;
position:relative;
}

div#dropMenu ul {
margin:0;
padding:0;
}

div#dropMenu li {
position:relative;
list-style:none;
margin:0;
float:left;
line-height:1em;
}

div#dropMenu ul.level1 {
width:70em;
margin:0 auto;
text-align:center;
font-weight: bold;
background:#2b2c89;
z-index:1000;
float:left;
}

div#dropMenu li:hover {font-weight: bold; color: #2b2c89;}
/*div#dropMenu li.submenu {background: url(../images/dropmenu.gif) 95% 50% no-repeat;}**/
div#dropMenu li.submenu:hover {}
div#dropMenu li a {display: block; padding: .6em 2em .6em 2em;text-decoration: none; text-transform:uppercase; color:#ffffff; text-align:center; border-right:1px solid #ffc708; border-left:1px solid #ffc708;}
div#dropMenu>ul a {width: auto;}
div#dropMenu ul ul {position: absolute; width: 12em;display: none;}
div#dropMenu ul ul li {border-bottom: 1px solid #CCC; width:12em;}
div#dropMenu li.submenu li.submenu {background: url(../images/submenu.gif) 98% 50% no-repeat;}
div#dropMenu ul.level1 li.submenu:hover ul.level2,
div#dropMenu ul.level2 li.submenu:hover ul.level3,
div#dropMenu ul.level3 li.submenu:hover ul.level4,
div#dropMenu ul.level4 li.submenu:hover ul.level5,
div#dropMenu ul.level5 li.submenu:hover ul.level6,
div#dropMenu ul.level6 li.submenu:hover ul.level7,
div#dropMenu ul.level7 li.submenu:hover ul.level8 {display:block;z-index:1000;}
div#dropMenu ul.level2 {background:#848484;z-index:1000;position:absolute;font-weight:normal;}
div#dropMenu ul.level3,
div#dropMenu ul.level4,
div#dropMenu ul.level5,
div#dropMenu ul.level6,
div#dropMenu ul.level7,
div#dropMenu ul.level8{top: 0; left: 12em; background:#848484}
div#dropMenu ul.level2 a {padding: 0.5em 0 0.5em 0.25em;color: white; text-transform:none;} /* this is text color on drop-down submenu */
div#dropMenu ul.level2 a:hover {color:#3986BF;}