TinyMCE button inserting wrong field name for category

The TinyMCE editor (version 2.7) inserts the category id instead of the category slug when inserting the shortcode. For example: category id for “documents” is 36:

Here is what is being inserted into the post/page:
[wpdm_tree category=”36″ download_link=1]

It should use the slug name and insert something like this:
[wpdm_tree category=”documents” download_link=1]

It has been like this for the past couple of versions — so I stopped using the TinyMCE button and just started copying the shortcodes manually.