Program: 11411
Project: 11411
Buggy source:
@Override public void mouseWheelMoved(GlimpseMouseEvent event){
  GlimpseAxisLayout2D layout=getAxisLayout(event);
  if (layout == null)   return;
  Axis2D axis2D=layout.getAxis(event.getTargetStack());
  double xTileDim=axis2D.getAxisX().getSizePixels() / 256;
  double yTileDim=axis2D.getAxisY().getSizePixels() / 256;
  double minX=axis2D.getAxisX().getMin();
  double maxX=axis2D.getAxisX().getMax();
  double minY=axis2D.getAxisY().getMin();
  double maxY=axis2D.getAxisY().getMax();
  LatLonGeo center=geoProj.unproject((minX + maxX) / 2.,(minY + maxY) / 2.);
  LatLonGeo ne=geoProj.unproject(maxX,maxY);
  LatLonGeo sw=geoProj.unproject(minX,minY);
  double east=ne.getLonDeg();
  double west=sw.getLonDeg();
  double lonSizeDeg=(east - west) / xTileDim;
  double zoomApprox=Math.log(360 / lonSizeDeg) / LOG2;
  int currentZoom=(int)Math.round(zoomApprox);
  int zoom=currentZoom;
  if (event.getWheelIncrement() == 0) {
  }
 else   if (event.getWheelIncrement() > 0) {
    zoom--;
  }
 else {
    zoom++;
  }
  zoom=Math.max(0,Math.min(zoom,MAX_ZOOM));
  if (zoom == currentZoom) {
    return;
  }
  double zoomFactor=1 << zoom;
  double lonTileSizeDeg=360 / zoomFactor;
  double latTileSizeDeg=170.1022 / zoomFactor;
  double dLat=(yTileDim / 2.) * latTileSizeDeg;
  double dLon=(xTileDim / 2.) * lonTileSizeDeg;
  Vector2d maxVec=geoProj.project(LatLonGeo.fromDeg(center.getLatDeg() + dLat,center.getLonDeg() + dLon));
  Vector2d minVec=geoProj.project(LatLonGeo.fromDeg(center.getLatDeg() - dLat,center.getLonDeg() - dLon));
  this.xSpan=maxVec.getX() - minVec.getX();
  this.ySpan=maxVec.getY() - minVec.getY();
  this.mouseWheelMoved(event,axis2D.getAxisX(),true);
  this.mouseWheelMoved(event,axis2D.getAxisY(),false);
  this.applyAndUpdate(axis2D.getAxisX(),axis2D.getAxisY());
}

Fixed version (ground truth):
@Override public void mouseWheelMoved(GlimpseMouseEvent event){
  GlimpseAxisLayout2D layout=getAxisLayout(event);
  if (layout == null)   return;
  Axis2D axis2D=layout.getAxis(event.getTargetStack());
  double xTileDim=axis2D.getAxisX().getSizePixels() / 256.;
  double yTileDim=axis2D.getAxisY().getSizePixels() / 256.;
  double minX=axis2D.getAxisX().getMin();
  double maxX=axis2D.getAxisX().getMax();
  double minY=axis2D.getAxisY().getMin();
  double maxY=axis2D.getAxisY().getMax();
  LatLonGeo center=geoProj.unproject((minX + maxX) / 2.,(minY + maxY) / 2.);
  LatLonGeo ne=geoProj.unproject(maxX,maxY);
  LatLonGeo sw=geoProj.unproject(minX,minY);
  double east=ne.getLonDeg();
  double west=sw.getLonDeg();
  double lonSizeDeg=(east - west) / xTileDim;
  double zoomApprox=Math.log(360 / lonSizeDeg) / LOG2;
  int currentZoom=(int)Math.round(zoomApprox);
  int zoom=currentZoom;
  if (event.getWheelIncrement() == 0) {
  }
 else   if (event.getWheelIncrement() > 0) {
    zoom--;
  }
 else {
    zoom++;
  }
  zoom=Math.max(0,Math.min(zoom,MAX_ZOOM));
  if (zoom == currentZoom) {
    return;
  }
  double zoomFactor=1 << zoom;
  double lonTileSizeDeg=360 / zoomFactor;
  double latTileSizeDeg=170.1022 / zoomFactor;
  double dLat=(yTileDim / 2.) * latTileSizeDeg;
  double dLon=(xTileDim / 2.) * lonTileSizeDeg;
  Vector2d maxVec=geoProj.project(LatLonGeo.fromDeg(center.getLatDeg() + dLat,center.getLonDeg() + dLon));
  Vector2d minVec=geoProj.project(LatLonGeo.fromDeg(center.getLatDeg() - dLat,center.getLonDeg() - dLon));
  this.xSpan=maxVec.getX() - minVec.getX();
  this.ySpan=maxVec.getY() - minVec.getY();
  this.mouseWheelMoved(event,axis2D.getAxisX(),true);
  this.mouseWheelMoved(event,axis2D.getAxisY(),false);
  this.applyAndUpdate(axis2D.getAxisX(),axis2D.getAxisY());
}