Nesting Lists

Hello. I'm trying to create a tree that is responsive when there are 1000's of items in it (and is always expanded). I have used this as a start point, but the repeater means that it is slow and unresponsive. I want to swap the repeater for a ListView, but if I just do a straight swap, the list is drawn over the top of the parent instead of underneath it, and subsequent items in the list are drawn over each other. The parent item sizes like I want it to, but if you just run the code in qmlscene and do the following:
Add Node-> node0
Add Node-> 0,n1
Add Node-> 0,n2
You can see that subchildren are not being drawn in the correct spot. I believe it's some interaction between the Column and the ListView, but I'm too much of a noob to be able to work out a solution. Can you please help. Full code is below, the ListView with ID objRepeater is what I'm trying to get working:
Code:
import QtQuick 2.0
import QtQuick.Window 2.0
import QtQuick.Layouts 1.0
import QtQuick.Controls 1.0
Rectangle {
   id: objRoot
   objectName: "objRoot"
   width: 600
   height: 600
   color: "black"
   ListModel {
      id: objModel
      objectName: "objModel"
   }
   Component {
      id: objRecursiveDelegate
      Item {
      Column {
         id: objRecursiveColumn
         objectName: "objRecursiveColumn"
         property int m_iIndex: model.index
         property var m_parentModel: model.parentModel
         clip: true
         MouseArea {
            id: objMouseArea
            objectName: "objMouseArea"
            width: objRow.implicitWidth
            height: objRow.implicitHeight
            onDoubleClicked: {
               for(var i = 0; i < parent.children.length; ++i) {
                  if(parent.children[i].objectName !== "objMouseArea") {
                     parent.children[i].visible = !parent.children[i].visible
                  }
               }
            }
            drag.target: objDragRect
            onReleased: {
               if(objDragRect.Drag.target) {
                  objDragRect.Drag.drop()
               }
            }
            Row {
               id: objRow
               Item {
                  id: objIndentation
                  height: 20
                  width: model.level * 20
               }
               Rectangle {
                  id: objDisplayRowRect
                  height: objNodeName.implicitHeight + objRepeater.contentHeight + 5
                  width: objCollapsedStateIndicator.width + objNodeName.implicitWidth + 5
                  border.color: "green"
                  border.width: 2
                  color: "#31312c"
                  DropArea {
                     keys: [model.parentModel]
                     anchors.fill: parent
                     onEntered: objValidDropIndicator.visible = true
                     onExited: objValidDropIndicator.visible = false
                     onDropped: {
                        objValidDropIndicator.visible = false
                        if(drag.source.m_objTopParent.m_iIndex !== model.index) {
                           objRecursiveColumn.m_parentModel.move(
                                    drag.source.m_objTopParent.m_iIndex,
                                    model.index,
                                    1
                                    )
                        }
                     }
                     Rectangle {
                        id: objValidDropIndicator
                        anchors.fill: parent
                        visible: false
                        onVisibleChanged: {
                           visible ? objAnim.start() : objAnim.stop()
                        }
                        SequentialAnimation on color {
                           id: objAnim
                           loops: Animation.Infinite
                           running: false
                           ColorAnimation { from: "#31312c"; to: "green"; duration: 400 }
                           ColorAnimation { from: "green"; to: "#31312c"; duration: 400 }
                        }
                     }
                  }
                  Rectangle {
                     id: objDragRect
                     property var m_objTopParent: objRecursiveColumn
                     Drag.active: objMouseArea.drag.active
                     Drag.keys: [model.parentModel]
                     border.color: "magenta"
                     border.width: 2
                     opacity: .85
                     states: State {
                        when: objMouseArea.drag.active
                        AnchorChanges {
                           target: objDragRect
                           anchors { horizontalCenter: undefined; verticalCenter: undefined }
                        }
                        ParentChange {
                           target: objDragRect
                           parent: objRoot
                        }
                     }
                     anchors { horizontalCenter: parent.horizontalCenter; verticalCenter: parent.verticalCenter }
                     height: objDisplayRowRect.height
                     width: objDisplayRowRect.width
                     visible: Drag.active
                     color: "red"
                     Text {
                        anchors.left: parent.left
                        height: 20
                        //horizontalAlignment: Text.AlignHCenter
                        //verticalAlignment: Text.AlignVCenter
                        text: model.name
                        font { bold: true; pixelSize: 18 }
                        color: "blue"
                     }
                  }
                  Text {
                     id: objCollapsedStateIndicator
                     anchors { left: parent.left; top: parent.top;}// bottom: parent.bottom }
                     width: 20
                     height: 20
                     //horizontalAlignment: Text.AlignHCenter
                     //verticalAlignment: Text.AlignVCenter
                     text: "+"//objRepeater.count > 0 ? objRepeater.visible ? qsTr("-") : qsTr("+") : qsTr("")
                     font { bold: true; pixelSize: 18}
                     color: "yellow"
                  }
                  Text {
                     id: objNodeName
                     anchors { left: objCollapsedStateIndicator.right; top: parent.top; }//bottom: parent.bottom }
                     text: model.name
                     height: 20
                     color: "yellow"//objRepeater.count > 0 ? "yellow" : "white"
                     font { bold: true; pixelSize: 18 }
                     //verticalAlignment: Text.AlignVCenter
                  }
               }
            }
         }
         Rectangle {
            id: objSeparator
            anchors { left: parent.left; right: parent.right; }
            height: 1
            color: "black"
         }
         ListView {
             anchors {top: objRecursiveColumn.bottom; left: parent.left; right: parent.right; bottom:parent.bottom;}
             //contentHeight: contentItem.childrenRect.height
             id: objRepeater
             objectName: "objRepeater"
             model: subNode
             delegate: objRecursiveDelegate
         }
      }
   }
   ColumnLayout {
      objectName: "objColLayout"
      anchors.fill: parent
      ScrollView {
         Layout.fillHeight: true
         Layout.fillWidth: true
         ListView {
            objectName: "objListView"
            model: objModel
            delegate: objRecursiveDelegate
            interactive: false
         }
      }
      Window {
         id: objModalInput
         objectName: "objModalInput"
         modality: Qt.ApplicationModal
         visible: false
         height: 30
         width: 200
         color: "yellow"
         TextInput {
            anchors.fill: parent
            font { bold: true; pixelSize: 20 }
            verticalAlignment: TextInput.AlignVCenter
            horizontalAlignment: TextInput.AlignHCenter
            validator: RegExpValidator {
               regExp: /(\d{1,},)*.{1,}/
            }
            onFocusChanged: {
               if(focus) {
                  selectAll()
               }
            }
            text: qsTr("node0")
            onAccepted: {
               if(acceptableInput) {
                  objModalInput.close()
                  var szSplit = text.split(',')
                  if(szSplit.length === 1) {
                     objModel.append({"name": szSplit[0], "level": 0, "parentModel": objModel, "subNode": []})
                  }
                  else {
                     if(objModel.get(parseInt(szSplit[0])) === undefined) {
                        console.log("Error - Given node does not exist !")
                        return
                     }
                     var node = objModel.get(parseInt(szSplit[0]))
                     for(var i = 1; i < szSplit.length - 1; ++i) {
                        if(node.subNode.get(parseInt(szSplit[i])) === undefined) {
                           console.log("Error - Given node does not exist !")
                           return
                        }
                        node = node.subNode.get(parseInt(szSplit[i]))
                     }
                     node.subNode.append({"name": szSplit[i], "level": i, "parentModel": node.subNode, "subNode": []})
                  }
               }
            }
         }
      }
      Button {
         text: "add data to tree"
         onClicked: {
            objModalInput.show()
         }
      }
   }
}