title: DropArea doesn't notify about actions onEntered, onExited, onDropped
body: <p>I have <code>Rectangle</code> filled with <code>MouseArea</code> which on <code>onPressAndHold()</code> handler reveals second <code>Rectangle</code> and transfers <code>drag</code> action to that <code>Rectangle</code>. The problem is that when I move that second <code>Rectangle</code> over <code>DropArea</code> it doesn't notify about any actions (<code>onEntered</code>, <code>onExited</code>, <code>onDropped</code>). I tried to do this in many combinations but it has never worked. Here is an example, am I missing something?</p>
  
  <pre><code>import QtQuick 2.0
  import QtQuick.Window 2.0
  
  Window {
      id: appDrawerRoot
      visible: true
      width: 360; height: 360
      property bool isRectVisible: false
  
      Rectangle{
          id:rect
          color: "blue"
          x:50; y:50
          width: 50; height: 50
  
          MouseArea{
              anchors.fill: parent
  
              onPressed: {
                  cloneRect.x = rect.x
                  cloneRect.y = rect.y
              }
              onPressAndHold: {
                  isRectVisible = true
                  drag.target = cloneRect
              }
              onReleased: {
                  drag.target = undefined
                  isRectVisible = false
                  cloneRect.x = rect.x
                  cloneRect.y = rect.y +100
              }
          }
      }
  
      Item{
          id: cloneRect
          width: 50; height:50
          visible: isRectVisible
  
          MouseArea{
              id: mouseArea
              width:50; height:50
              anchors.centerIn: parent
  
              Rectangle{
                  id:tile
                  width: 50; height:50
                  color:"black"
                  opacity: 0.5
                  anchors.verticalCenter: parent.verticalCenter
                  anchors.horizontalCenter: parent.horizontalCenter
                  Drag.hotSpot.x: 25
                  Drag.hotSpot.y: 25
              }
          }
      }
  
      DropArea {
          id:dropArea
          x:153
          y:158
          z:-1
          width:100; height: 100
  
          Rectangle{
              anchors.fill: parent
              color: "Green"
          }
          onEntered: {
              drag.source.opacity = 1
              console.log("ENTERED")
          }
          onExited: {
              drag.source.opacity = 0.5
              console.log("EXITED")
          }
          onDropped:
          {
              console.log("DROPPED")
          }
      }
  }
  </code></pre>