ActiveSelect does not work with custom themes

Activeselect does not seem to work with the definition of theme_regions() in the tempalte.php file. I am not sure why this will affect activeselect.

After defining my customtheme_regions() {} in template.php - the drop down menus in a node defined by the category module do not change. The "loading circle" keeps rotating in the "parent" active select while the other drop down box contains the list of all children (which does not change irrespective of what item i choose from the
"parent" drop down box. )