Question ListView element not respecting width style

I have a ListView with a vertical list of elements.

Both the listView and the element template have been styled with width: 100%

The ListView fills up it's container's width.

The elements in the list view do not fill up the width of the list view. There are large gaps on the sides. I tried different alignment options on the element template, but nothing seems to work.

Is there a trick here?

 

It turns out the style.width property of the template's root element is for some reason null when setting up my element references inside the template's class. I created a class for data binding on the list elements as per the docs on listview.

I can manually style it in code here with style.width = new StyleLength(500) and it works.

But if I use width = Length.Percent(100) it goes back to being short, and does not use the full width.

I don't understand why it's null, or why it doesn't use 100% width when it's not null, but pixel sizing seems to work. I don't know if it's a bug or what.

Edit: I changed the flex settings for the container to stretch and it works as expected. Not sure why 100% width doesn't work.