This can happen, if you attach MagicSuggest to an input element declared with a value attribute.
Explanation:
This will not work:
<input type="text" name="klip_tags" id="klip-tags" value="" />
This will not work:
<input type="text" name="klip_tags" id="klip-tags" value="joomla,javascript" />
This will work:
<input type="text" name="klip_tags" id="klip-tags" />