Making Arguments Work with Dropdown Categories in Admin Section

I am trying to add a second category box on the admin write page. I want one category box to contain commonly used categories and the second box to contain all categories.

In the wpedit-form-advanced.php file I found the code to produce the dropdown categories:

<fieldset id=”categorydiv” class=”dbx-box”>
<h3 class=”dbx-handle”><?php _e(‘Categories’) ?></h3>
<div class=”dbx-content”>
<p id=”jaxcat”></p>
<ul id=”categorychecklist”><?php dropdown_categories(); ?></div>
</fieldset>

I repeated that code and it gave me a new box, but when I try to limit the categories with arguments, I couldn’t get it to work. I’ve tried excluding, like this:

<?php dropdown_categories(‘exclude=1,3’); ?>

I’ve tried including categories too (which would be better, actually).

<?php dropdown_categories(2); ?>

Am I doing this wrong or missing something? Do I need to make changes elsewhere?