I have following ListView:
Qt Code: 
  1. import QtQuick 2.5
  2. import QtQuick.Layouts 1.2
  3.  
  4. import si.mikroelektronika 1.0
  5.  
  6. Item
  7. {
  8.     id: ueCategorySelector
  9.  
  10.     clip: true
  11.  
  12.     Rectangle
  13.     {
  14.         id: ueCategorySelectorWrapper
  15.  
  16.         radius: 16
  17.         gradient: Gradient
  18.         {
  19.             GradientStop
  20.             {
  21.                 position: 0
  22.                 color: "#ffffff"
  23.             }   // GradientStop
  24.  
  25.             GradientStop
  26.             {
  27.                 position: 1
  28.                 color: "#000000"
  29.             }   // GradientStop
  30.         }   // Gradient
  31.  
  32.         border.color: "#4682b4"
  33.         border.width: 1
  34.  
  35.         antialiasing: true
  36.  
  37.         anchors.fill: parent
  38.  
  39.         ColumnLayout
  40.         {
  41.             anchors.margins: parent.radius/2
  42.  
  43.             spacing: 0
  44.             antialiasing: true
  45.  
  46.             anchors.fill: parent
  47.  
  48.             ListView
  49.             {
  50.                 id: ueCategoryListView
  51.  
  52.                 antialiasing: true
  53.  
  54.                 orientation: ListView.Horizontal
  55.                 clip: true
  56.  
  57.                 Layout.fillWidth: true
  58.                 Layout.fillHeight: true
  59.                 Layout.alignment: Qt.AlignHCenter|Qt.AlignVCenter
  60.                 Layout.margins: 8
  61.  
  62.                 spacing: 8
  63.  
  64.                 populate: Transition
  65.                 {
  66.                     NumberAnimation
  67.                     {
  68.                         property: "opacity"
  69.                         from: 0
  70.                         to: 1
  71.                         duration: 100
  72.                     }   // NumberAnimation
  73.                 }
  74.  
  75.                 Component.onCompleted:
  76.                 {
  77.                     model=ueCategoriesModel
  78.                 }   // Component.onCompleted
  79.  
  80.                 delegate: Rectangle
  81.                 {
  82.                     id: ueCategorySelectorDelegate
  83.  
  84.                     radius: 16
  85.  
  86.                     width: 256
  87.                     height: ueCategoryListView.height-2*Layout.margins
  88.  
  89.                     clip: true
  90.  
  91.                     border.color: "#4682b4"
  92.  
  93.                     antialiasing: true
  94.  
  95.                     gradient: Gradient
  96.                     {
  97.                         GradientStop
  98.                         {
  99.                             position: 0
  100.                             color: "#000000"
  101.  
  102.                             ParallelAnimation on color
  103.                             {
  104.                                 id: ueCategorySelectorColorAnimation
  105.  
  106.                                 loops: 1
  107.                                 running: false
  108.  
  109.                                 ColorAnimation
  110.                                 {
  111.                                     from: "#4682b4"
  112.                                     to: "#000000"
  113.                                     duration: 100
  114.                                 }   // ColorAnimation
  115.                             }   // ParallelAnimation
  116.                         }   // GradientStop
  117.  
  118.                         GradientStop
  119.                         {
  120.                             position: 1
  121.                             color: "#ffffff"
  122.                         }   // GradientStop
  123.                     }   // Gradient
  124.  
  125.                     MouseArea
  126.                     {
  127.                         id: ueDelegateMouseArea
  128.  
  129.                         anchors.fill: parent
  130.  
  131.                         onClicked:
  132.                         {
  133.                             ueCategorySelectorColorAnimation.running=true;
  134.                             ueProductsModel.ueUpdateProducts(model.ueRoleId)
  135.                             ueProductSelectorOpacityAnimator.running=true;
  136.  
  137.                             ueCategoryListView.currentIndex=index
  138.                         }   // onClicked
  139.                     }   // MouseArea
  140.  
  141.                     ColumnLayout
  142.                     {
  143.                         anchors.fill: parent
  144.  
  145.                         antialiasing: true
  146.  
  147.                         spacing: 8
  148.  
  149.                         Image
  150.                         {
  151.                             Layout.fillWidth: true
  152.                             Layout.fillHeight: true
  153.                             Layout.alignment: Qt.AlignHCenter|Qt.AlignTop
  154.                             Layout.topMargin: ueCategorySelectorWrapper.radius+4
  155.  
  156.                             fillMode: Image.PreserveAspectFit
  157.  
  158.                             horizontalAlignment: Image.AlignHCenter
  159.                             verticalAlignment: Image.AlignVCenter
  160.  
  161.                             antialiasing: true
  162.                             source: "image://ueCategoriesModel/"+model.ueRoleImage
  163.                         }   // Image
  164.  
  165.                         Text
  166.                         {
  167.                             Layout.fillWidth: true
  168.                             Layout.fillHeight: true
  169.                             Layout.alignment: Qt.AlignHCenter|Qt.AlignBottom
  170.                             Layout.bottomMargin: ueCategorySelectorWrapper.radius+4
  171.  
  172.                             color: "#000000"
  173.  
  174.                             text: model.ueRoleName
  175.                             wrapMode: Text.WordWrap
  176.                             font.family: "Courier"
  177.                             textFormat: Text.RichText
  178.  
  179.                             font.bold: true
  180.                             font.pointSize: 10
  181.  
  182.                             horizontalAlignment: Text.AlignHCenter
  183.                             verticalAlignment: Text.AlignVCenter
  184.                         }   // Text
  185.                     }   // ColumnLayout
  186.                 }   // delegate
  187.             }   // ListView
  188.         }   // ColumnLayot
  189.     }   // Rectangle
  190.  
  191.     ListView.onAdd:
  192.     {
  193.         print("Add")
  194.     }
  195. }   // Item
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Why does ListView not call populate transition?

Sincerely,
Marko