iview/src/styles/components/dropdown.less

@dropdown-prefix-cls: ~"@{css-prefix}dropdown";
@dropdown-item-prefix-cls: ~"@{dropdown-prefix-cls}-item";

.@{dropdown-prefix-cls} {
    display: inline-block;
    //position: relative;

    .@{select-dropdown-prefix-cls} {
        overflow: visible;
        max-height: none;
    }
    .@{dropdown-prefix-cls} {
        width: 100%;
    }

    &-rel{
        //display: inline-block;
        position: relative;
    }

    &-menu{
        min-width: 100px;
    }

    &-transfer{
        width: auto;
    }
}

.select-item(@dropdown-prefix-cls, @dropdown-item-prefix-cls);