Remove clickHandler from 1 item in combobox

hello everyone,

I’m using a combobox to map out my menu.
Some buttons in my menu don’t have pages only sub pages, these pages have to be visible in the combobox but not active. when i choose a inactive one the combobox there should be no action and it shouldn’t collapse.

So the question is how do i make a item in the combobox inactive?

I hope someone will understand what i mean.

thanx in advance,

Maxgrafx