Program: 65913
Project: 65913
Buggy source:
public int canDrop(Object transfer,Object target,int operation,DNDLocation location){
  if ((transfer.equals(DesignerPaletteFactory.AGG_TEMPLATE) || transfer.equals(DesignerPaletteFactory.TIMEPERIOD_TEMPLATE)) && target instanceof CrosstabCellEditPart) {
    CrosstabCellAdapter adapter=(CrosstabCellAdapter)((CrosstabCellEditPart)target).getModel();
    if (adapter.getCrosstabCellHandle() != null && DEUtil.isReferenceElement(adapter.getCrosstabCellHandle().getCrosstabHandle()))     return DNDService.LOGIC_FALSE;
    String posType=adapter.getPositionType();
    if (ICrosstabCellAdapterFactory.CELL_MEASURE_AGGREGATION.equals(posType) || ICrosstabCellAdapterFactory.CELL_MEASURE.equals(posType)) {
      return DNDService.LOGIC_TRUE;
    }
  }
  return DNDService.LOGIC_UNKNOW;
}

Fixed version (ground truth):
public int canDrop(Object transfer,Object target,int operation,DNDLocation location){
  if ((transfer.equals(DesignerPaletteFactory.AGG_TEMPLATE) || transfer.equals(DesignerPaletteFactory.TIMEPERIOD_TEMPLATE)) && target instanceof CrosstabCellEditPart) {
    CrosstabCellAdapter adapter=(CrosstabCellAdapter)((CrosstabCellEditPart)target).getModel();
    if (adapter.getCrosstabCellHandle() != null && DEUtil.isReferenceElement(adapter.getCrosstabCellHandle().getCrosstabHandle()))     return DNDService.LOGIC_FALSE;
    String posType=adapter.getPositionType();
    if (ICrosstabCellAdapterFactory.CELL_MEASURE_AGGREGATION.equals(posType) || ICrosstabCellAdapterFactory.CELL_MEASURE.equals(posType)) {
      if (transfer.equals(DesignerPaletteFactory.TIMEPERIOD_TEMPLATE)) {
        CrosstabReportItemHandle reportHandle=adapter.getCrosstabCellHandle().getCrosstab();
        if (DEUtil.isReferenceElement(reportHandle.getCrosstabHandle())) {
          return DNDService.LOGIC_FALSE;
        }
        CubeHandle cube=reportHandle.getCube();
        if (cube == null) {
          return DNDService.LOGIC_FALSE;
        }
        if (cube.getPropertyHandle(ICubeModel.DIMENSIONS_PROP) == null) {
          return DNDService.LOGIC_FALSE;
        }
        List list=cube.getPropertyHandle(ICubeModel.DIMENSIONS_PROP).getContents();
        for (int i=0; i < list.size(); i++) {
          DimensionHandle dimension=(DimensionHandle)list.get(i);
          if (CrosstabAdaptUtil.isTimeDimension(dimension)) {
            DimensionViewHandle viewHandle=reportHandle.getDimension(dimension.getName());
            if (viewHandle == null) {
              int count=dimension.getDefaultHierarchy().getLevelCount();
              if (count == 0) {
                continue;
              }
              LevelHandle levelHandle=dimension.getDefaultHierarchy().getLevel(0);
              if (DesignChoiceConstants.DATE_TIME_LEVEL_TYPE_YEAR.equals(levelHandle.getDateTimeLevelType())) {
                return DNDService.LOGIC_TRUE;
              }
            }
 else {
              int count=viewHandle.getLevelCount();
              if (count == 0) {
                continue;
              }
              LevelViewHandle levelViewHandle=viewHandle.getLevel(0);
              if (DesignChoiceConstants.DATE_TIME_LEVEL_TYPE_YEAR.equals(levelViewHandle.getCubeLevel().getDateTimeLevelType())) {
                return DNDService.LOGIC_TRUE;
              }
            }
          }
        }
        return DNDService.LOGIC_FALSE;
      }
 else {
        return DNDService.LOGIC_TRUE;
      }
    }
  }
  return DNDService.LOGIC_UNKNOW;
}