Have you eliminated the <br /> after the category name output?
(In /includes/templates/your_template/sideboxes/tpl_categories.php.)
That is required for the stock inline link elements to display correctly, but causes the gap when displaying as block or list-item.
You could look at the Categories Dressing code if you want more pointers.
You can add
margin-left: -3px;
to move the button edge (adjust to taste).



