subcategory title and empty ul showing when no subcats

[babyewok]

I have just noticed that The Subcategorys heading and empty ul are showing on categories that have no subcategories.

 

This occurs in the default theme and the custom theme I am working on.  I have v 1.4.11

 

Has any one else experienced this issue?  What is causing it?  I have

{if isset($subcategories)}

but it seems ot be ignoring it