materialize: Dropdowns not working

@Dogfalo, did something change on dropdown’s structure? I have this for button:

<a class="dropdown-button" href="#!" data-activates="dropdowngerencial">
    Gerencial <i class="mdi-navigation-arrow-drop-down right"></i>
</a>

and this for content:

<ul id="dropdowngerencial" class="dropdown-content">
    <li>
        <a href="@Url.Action("Index", "Lancamento", new { area = "Gerencial" })" >Lan&ccedil;amentos</a>
    </li>
    <li>
        <a href="@Url.Action("Index", "Historico", new { area = "Gerencial" })" >Hist&oacute;rico</a>
    </li>
</ul>