By default, `tc-drop-down` applies CSS `white-space:nowrap`. In addition, for links it also applies `display:block; padding:0 14px 0 14px;`.
To override these default styles, you can define and apply your own CSS class (e.g., "my-drop-down"), like this:
1) Create a stylesheet tiddler, tagged with `$:/tags/Stylesheet`, containing:
.my-drop-down { white-space:normal; }
.my-drop-down a { display:inline; padding:0; }
2) Then, where you display your dropdown `<div>`, add `my-drop-down` to the class, like this:
<div class="tc-drop-down my-drop-down">
<$transclude tiddler="HelloThere" mode="block"/>
</div>
enjoy,
-e