slickgrid/plugins/slick.headermenu.css

/* Menu button */
.slick-header-menubutton {
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 14px;
  background-repeat: no-repeat;
  background-position: left center;
  background-image: url(../images/down.gif);
  cursor: pointer;

  display: none;
  border-left: thin ridge silver;
}

.slick-header-column:hover > .slick-header-menubutton,
.slick-header-column-active .slick-header-menubutton {
  display: inline-block;
}

/* Menu */
.slick-header-menu {
  position: absolute;
  display: inline-block;
  margin: 0;
  padding: 2px;
  cursor: default;
}


/* Menu items */
.slick-header-menuitem {
  list-style: none;
  margin: 0;
  padding: 0;
  cursor: pointer;
  display: block;
}

.slick-header-menuicon {
  display: inline-block;
  width: 16px;
  height: 16px;
  vertical-align: middle;
  margin-right: 4px;
  background-repeat: no-repeat;
  background-position: center center;
}

.slick-header-menucontent {
  display: inline-block;
  vertical-align: middle;
}


/* Disabled */
.slick-header-menuitem-disabled {
  color: silver;
}

/* Hidden */
.slick-header-menuitem-hidden {
  display: none;
}

/* Divider */
.slick-header-menuitem.slick-header-menuitem-divider {
  cursor: default;
  border: none;
  overflow: hidden;
  padding: 0;
  height: 1px;
  margin: 8px 2px;
  background-color: #cecece;
}
.slick-header-menuitem-divider.slick-header-menuitem:hover {
  background-color: #cecece;
}