How can I make a WPF Expander Stretch?

Question

The Expander control in WPF does not stretch to fill all the available space. Is there any solutions in XAML for this?

Answer 1

I am pretty surprised nobody has mentioned to just edit the control template, all the other solutions have some pretty serious drawbacks weather its not calculating width properly, not redrawing, render time etc...

This control template will modify the header's contentpresenter horizontal alignment to match the actual expanders (meaning it will stretch)