WPF- ListBoxItem border is sometimes hidden behind the ListBox's scrollbar.

Question

Most of the time the ListBox appears like this:

But every once in a while it looks like this:

Any idea of what is going wrong?

--Edit--

I removed the control templates from the question, because when I removed them from my program the problem still existed. Is this a WPF bug?

Answer 1

Have you tried setting SnapsToDevicePixels="True" on the ListBox Item border? Since the thickness is 1 "Device independent unit" I am thinking that the border is falling on a pixel boundry.