title: QML - setting width and height has no effect
body: <p>Quick Controls 2, Qt 5.10. </p>
  
  <p>I created table control based on <code>ListView</code> item.</p>
  
  <p>One of its columns is displayed using this component:</p>
  
  <pre><code>import QtQuick 2.10
  import QtQuick.Controls 2.3
  import QtQuick.Layouts 1.3
  
  Item
  {
      id: root
  
      implicitHeight: item1.implicitHeight
  
      ColumnLayout
      {
          id: item1
  
          visible: !model.finished
          width: parent.width
  
          RowLayout
          {
              Label
              {
                  text: "38%"
                  Layout.alignment: Qt.AlignLeft
              }
  
              Label
              {
                  text: "Paused"
                  Layout.alignment: Qt.AlignRight
              }
          }
  
          ProgressBar
          {
              from: 0; to: 100; value: 40
              // Variant A
              /*Layout.preferredWidth: 30
              Layout.preferredHeight: 10*/
              // Variant B
              width: 30
              height: 10
          }
      }
  }
  </code></pre>
  
  <p>Can somebody please explain me why Variant B does not "work". I may specify any width/height values or even just remove them - no effect. Variant A (Layout.preferredWidth/Layout.preferredHeight) works fine. </p>
  
  <p>Variant A: </p>
  
  <p><a href="https://i.stack.imgur.com/CSjyM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CSjyM.png" alt="enter image description here"></a></p>
  
  <p>Variant B:</p>
  
  <p><a href="https://i.stack.imgur.com/opSJF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/opSJF.png" alt="enter image description here"></a></p>