jQuery('#filterSelect').multiselect({
    columns: 1,
    placeholder: 'Select Class Filters',
    data: {
            src: [
                {% for sign_type in sign_types %}
                "{{ sign_type.value }}"
                {%- if not loop.last -%}
                ,
                {% endif %}
                {% endfor %}
            ]},
    search: true,
    selectAll:true,
});

<select name="filterSelect[]" multiple id="filterSelect">
    <option value="Background">Background</option>
    <option value="Checkpoint_TollStation">Checkpoint_TollStation</option>
    <option value="Indication_CameraSurveillance">Indication_CameraSurveillance</option>
    <option value="Mandatory_MinimumSpeedLimitBegin">Mandatory_MinimumSpeedLimitBegin</option>
    <option value="Mandatory_MinimumSpeedLimitEnd">Mandatory_MinimumSpeedLimitEnd</option>
    <option value="Mandatory_PassOnEitherSide">Mandatory_PassOnEitherSide</option>
    <option value="Mandatory_PassOnThisSideLeft">Mandatory_PassOnThisSideLeft</option>
    <option value="Mandatory_PassOnThisSideRight">Mandatory_PassOnThisSideRight</option>
    <option value="Mandatory_ProceedStraight">Mandatory_ProceedStraight</option>
    <option value="Mandatory_ProceedStraightOrTurnLeft">Mandatory_ProceedStraightOrTurnLeft</option>
    <option value="Mandatory_ProceedStraightOrTurnRight">Mandatory_ProceedStraightOrTurnRight</option>
    <option value="Mandatory_Roundabout">Mandatory_Roundabout</option>
</select>