AUI Dropdown2 in IssueTabPanel won't render

Trying to render AUI dropdown elements within an IssueTabPanel.

Using both JiraWebResourceManager, my .vm starts with:

$webResourceManager.requireResourcesForContext("myContext")

In my atlassian-plugin.xml:

 <web-resource key="myResourceKey" name="My Web Resources"> 
    <dependency>com.atlassian.auiplugin:ajs</dependency>
    <dependency>com.atlassian.auiplugin:aui-button</dependency>
    <dependency>com.atlassian.auiplugin:aui-dropdown2</dependency>
    <!-- other things -->
    <context>myContext</context>
</web-resource>

Trying sample straight from the AUI documentation:

<button class="aui-button aui-dropdown2-trigger" aria-controls="radio-items">
    Dropdown menu
</button>
<aui-dropdown-menu id="radio-items">
    <aui-section label="Browsers">
        <aui-item-radio interactive checked>Chrome</aui-item-radio>
        <aui-item-radio interactive>Firefox</aui-item-radio>
        <aui-item-radio interactive>Safari</aui-item-radio>
    </aui-section>
</aui-dropdown-menu>

Other elements, like toggles, work just fine.