Page {
  property bool bannerStart: false

  ListView {
    onContentYChanged: {
      if (bannerStart && (contentY <= params.bannerMargin))
        showPullDownItem(); 
    }
    onMovementStart: {
      if (contentY==0) bannerStart = true;
      else                    bannerStart = false;
    }
    onVerticalVelocityChanged: {
      // Prevent triggering pulldown item when rebound from top boundary.
      if (verticalVelocity>0) bannerStart = false;
    }
    onMovementEnded: {
      bannerStart = false;
      // trigger timer to hide pull-down item 
      timer.restart();
    }
  }
}