This due to customized code on your site
Open templates/uwerk/css/custom.css file
Change
.dropdown-menu {
position: absolute;
top: 100%;
left: 0;
z-index: 1000;
display: block !important;
float: left;
min-width: 160px;
list-style: none;
background-color: #fff
border: 0px ;
border: 0px ;
padding: 0;
margin: 0;
-webkit-border-radius: 0 0 0 0;
-moz-border-radius: 0 0 0 0;
border-radius: 0 0 0 0;
-webkit-box-shadow: 0 0 0 rgba(0,0,0,0);
-moz-box-shadow: 0 0 0 rgba(0,0,0,0);
box-shadow: 0 0 rgba(0,0,0,0);
-webkit-background-clip: padding-box;
-moz-background-clip: padding;
background-clip: padding-box;
}
To
.dropdown-menu {
position: inherit;
top: 100%;
left: 0;
z-index: 1000;
display: block !important;
float: left;
min-width: 160px;
list-style: none;
background-color: #fff
border: 0px ;
border: 0px ;
padding: 0;
margin: 0;
-webkit-border-radius: 0 0 0 0;
-moz-border-radius: 0 0 0 0;
border-radius: 0 0 0 0;
-webkit-box-shadow: 0 0 0 rgba(0,0,0,0);
-moz-box-shadow: 0 0 0 rgba(0,0,0,0);
box-shadow: 0 0 rgba(0,0,0,0);
-webkit-background-clip: padding-box;
-moz-background-clip: padding;
background-clip: padding-box;
}