HoverHandler is unreliable

Please try the following example (tested on macOS only).

This a a simple ListView with delegates made of Buttons with hoverEnabled. The HoverHandler is supposed to detect whether the mouse is inside the listview (yellow framing) or outside (gray framing). The buttons have a lovely green color when hovered.

• Minor problem: If the mouse cursor is actually inside the ListView after program start, HoverHandler's hovered is reported as false. Surprisingly, the delegate button's hovered state is correct (green). Only after some movement where the spacing between the delegates is hit the state is updated.

• Major problem: After clicking a button, the HoverHandler's hovered property is no longer updated (ListView gray frame). This seems to be fixed again by hovering some part of the list view that is not covered by a delegate (e.g. spacing).

With QT_LOGGING_RULES=qt.quick.handler.dispatch=true I can see

qt.quick.handler.dispatch: QQuickHoverHandler "" on QQuickListView "" DECLINES QQuickPointerEvent(0 dev:Mouse [QQuickEventPoint(accepted:true state:Updated scenePos:QPointF(33,226) id:1000000 timeHeld:3.943) ])

in the debug output until the problem is magically fixed again (note the DECLINES).

My workaround is to use an EventFilter on the ListView to capture QEvent::HoverEnter and QEvent::HoverLeave, which works fine as those events are always being delivered as expected.

The InputHandler mechanics seem to be quite complex (grabbing, non-grabbing Pointer handlers etc.) so I suspect something evil at work there.

Test case:

import QtQuick 2.12
import QtQuick.Controls 2.12
import QtQuick.Window 2.12

Window {
  visible: true
  width: 640
  height: 480
  title: qsTr("Hello World")


  Rectangle {
    color: hh.hovered ? "yellow" : "gray"
    anchors { fill: lv; margins: -5 }
  }

  ListView {
    id: lv
    anchors.fill: parent
    anchors.margins: 40
    model: 100
    spacing: 1
    clip: true
    interactive: false

    delegate: Button {
      id: control
      width: lv.width
      height: 40
      hoverEnabled: true // if not set by style
//      hoverEnabled: false // without hoverEnabled false, bug does not occur
      leftPadding: 8
      rightPadding: 8
      text: "This is a Text " + model.index
      onClicked: console.log("Clicked")
      background: Rectangle {
        color: control.hovered ? "green" : "red"
      }
    }

    HoverHandler {
      id: hh
    }
  }
}