Program: 170443
Project: 170443
Buggy source:
@Override public boolean dragAdjust(final Point2D dxy){
  int x=(int)(m_startX + dxy.getX());
  int y=(int)(m_startY + dxy.getY());
  String colorKey=BackingColorMapUtils.findColorAtPoint(m_shapesBacking,x,y);
  if (m_colorKey != null && colorKey != null && !colorKey.equals(m_colorKey)) {
    if (null != m_magnets) {
      m_magnets.hide();
    }
    m_magnets=null;
    m_colorKey=null;
  }
  boolean isAllowed=true;
  if (m_magnets == null) {
    isAllowed=checkAllowAndShowMagnets(colorKey);
  }
  m_connector.updateForSpecialConnections();
  if (isAllowed) {
    if (null != m_magnets) {
      String magnetColorKey=BackingColorMapUtils.findColorAtPoint(m_magnetsBacking,x,y);
      if (magnetColorKey == null) {
        if (null != m_magnets) {
          m_magnets.hide();
        }
        m_magnets=null;
        m_colorKey=null;
        m_current_magnet=null;
      }
 else {
        WiresMagnet potentialMagnet=m_magnet_color_map.get(magnetColorKey);
        if (m_connector.getHeadConnection().getMagnet() != potentialMagnet && m_connector.getTailConnection().getMagnet() != potentialMagnet) {
          m_current_magnet=potentialMagnet;
        }
 else         if (potentialMagnet == null) {
          m_current_magnet=null;
        }
      }
    }
    if (null != m_current_magnet) {
      Shape<?> control=m_current_magnet.getControl().asShape();
      if (control != null) {
        Point2D absControl=control.getComputedLocation();
        double targetX=absControl.getX();
        double targetY=absControl.getY();
        double dx=targetX - m_startX - dxy.getX();
        double dy=targetY - m_startY - dxy.getY();
        if (dx != 0 || dy != 0) {
          dxy.setX(dxy.getX() + dx).setY(dxy.getY() + dy);
        }
      }
    }
    return true;
  }
  return false;
}

Fixed version (ground truth):
@Override public boolean dragAdjust(final Point2D dxy){
  int x=(int)(m_startX + dxy.getX());
  int y=(int)(m_startY + dxy.getY());
  String colorKey=BackingColorMapUtils.findColorAtPoint(m_shapesBacking,x,y);
  if (m_colorKey != null && colorKey != null && !colorKey.equals(m_colorKey)) {
    if (null != m_magnets) {
      m_magnets.hide();
    }
    m_magnets=null;
    m_colorKey=null;
  }
  boolean isAllowed=true;
  if (m_magnets == null) {
    isAllowed=checkAllowAndShowMagnets(colorKey);
  }
  m_connector.updateForSpecialConnections(false);
  if (isAllowed) {
    if (null != m_magnets) {
      String magnetColorKey=BackingColorMapUtils.findColorAtPoint(m_magnetsBacking,x,y);
      if (magnetColorKey == null) {
        if (null != m_magnets) {
          m_magnets.hide();
        }
        m_magnets=null;
        m_colorKey=null;
        m_current_magnet=null;
      }
 else {
        WiresMagnet potentialMagnet=m_magnet_color_map.get(magnetColorKey);
        if (m_connector.getHeadConnection().getMagnet() != potentialMagnet && m_connector.getTailConnection().getMagnet() != potentialMagnet) {
          m_current_magnet=potentialMagnet;
        }
 else         if (potentialMagnet == null) {
          m_current_magnet=null;
        }
      }
    }
    if (null != m_current_magnet) {
      Shape<?> control=m_current_magnet.getControl().asShape();
      if (control != null) {
        Point2D absControl=control.getComputedLocation();
        double targetX=absControl.getX();
        double targetY=absControl.getY();
        double dx=targetX - m_startX - dxy.getX();
        double dy=targetY - m_startY - dxy.getY();
        if (dx != 0 || dy != 0) {
          dxy.setX(dxy.getX() + dx).setY(dxy.getY() + dy);
        }
      }
    }
    return true;
  }
  return false;
}