static/themes/metro-green/combo.css

.combo-arrow {
  width: 18px;
  height: 20px;
  overflow: hidden;
  display: inline-block;
  vertical-align: top;
  cursor: pointer;
  opacity: 0.6;
  filter: alpha(opacity=60);
}
.combo-arrow-hover {
  opacity: 1.0;
  filter: alpha(opacity=100);
}
.combo-panel {
  overflow: auto;
}
.combo-arrow {
  background: url('images/combo_arrow.png') no-repeat center center;
}
.combo-panel {
  background-color: #fafafa;
}
.combo-arrow {
  background-color: #e5f0c9;
}
.combo-arrow-hover {
  background-color: #E0F892;
}
.combo-arrow:hover {
  background-color: #E0F892;
}
.combo .textbox-icon-disabled:hover {
  cursor: default;
}