WPF , Getting verticalstretch working as expected!

Question

I am trying to make the vertical stretch to work as expected i WPF, but for some reason it only takes the space it needs, and not the space available.

First, I am using

Answer 1

I found a solution. I have to override the ItemsPanel Template to use a grid (or similar container):

I have also in this case removed some of the xaml to make it more readble!

Thanks