Well, I needed to take this a step further to be able to add custom post types and pull them out separately, not just as a group. So here is what I did (hope this helps someone else):
1. Around line 1477, add your extra types. just copy the line from post type 2:
'<option value="2"'.( $post_type==2 ? ' selected="selected"' : '' ).'>'.__( 'Pages only', $this->plugin_alias ).'</option>'.
and add one line for each type you need.
2. around line 889, add a new case type for each new post type, and make the number correspond as with the others.
3. VERY IMPORTANT: around line 1277 (or 1278) change this line:
'post_type' => intval( preg_replace( '#[^012]#', '', $new_instance['post_type'] ) ),
to something like
'post_type' => intval( preg_replace( '#[^01234567]#', '', $new_instance['post_type'] ) ),
add a number for each of your post types.
Et Voila! Now in the widget you can pick from any of your defined post types…