Can I disable the auto-fill for the Norton toolbar Safe Search?

"Autofill" when searching is usually a helpful thing but I get frustrated when I use the Search box on the Norton Toolbar. At some point (probably related to the number of possible hits it has found and is suggesting), it stops you from keying in any more letters.

 

I usually only notice this when I've finished keying in the search word, of which only the first four or five letters have actually been entered.

 

Is there any way that I can disable the Autofill action?