WPF - setting HorizontalAlignment= Stretch to Textbox in StackPanel

Question

Why doesn\'t a textbox stretch to fill space in a stackpanel? Is this by design? In a grid, the textbox stretches as expected.

Answer 1

I needed items to be sized evenly, but stacked vertically.

I used a UniformGrid, and set the Columns property to 1. (tested with a TextBox, and it stretches like you want)