I'm trying to put 5 buttons in my window, aligned in a row, and each button should have equal width, while occupying all the available space in the parent. Here's how I'm trying (fails):
Row {
      id: toolbar
      width: 300
      height: 80
      Button {
        text: "left"
      }
      Button {
        text: "right"
      }
      Button {
        text: "tab"
      }
      Button {
        text: "home"
      }
      Button {
        text: "end"
      }
}
In this example, the Button items won't be resized to fit in their parent. I would like to see each Button get 1/5 of their parent's width. Obviously, using Row isn't enough. 
Also, using:
width: parent.width / parent.children.count
in each Button fails, as parent.children.count is undefined. One could use Component.onCompleted to set the width, when everything is already prepared, but there has to be a better way.
Is there an option of Row which enforces a width on its children? Or what other layout option is there?