Gaps between items in my ListBox

Question

When I create ListBox with horizontal items ordering for example like this:

Answer 1

Those gaps are inside the ControlTemplate of the ListViewItems, you'd have to override that i'm afraid...

Edit: On some platforms you do not even need to mess with the Template to get rid of the gaps between items:

To get rid of the gap at the very side you actually need to change the ListBox ControlTemplate itself, it's not a matter of the items. In the default Aero template there is a border with Padding = 1