Bug 136270 Group's data binding column can only be used by the group itself
If you add some data binding columns to a group, these columns can only be used by this group itself. It should has a way to make the child can use the parent group's data binding column.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
import org.eclipse.birt.report.model.api.CellHandle;
import org.eclipse.birt.report.model.api.ComputedColumnHandle;
import org.eclipse.birt.report.model.api.DataItemHandle;
import org.eclipse.birt.report.model.api.DataSetHandle;
import org.eclipse.birt.report.model.api.DataSourceHandle;
import org.eclipse.birt.report.model.api.DesignElementHandle;
import org.eclipse.birt.report.model.api.DesignEngine;
import org.eclipse.birt.report.model.api.DimensionHandle;
import org.eclipse.birt.report.model.api.GraphicMasterPageHandle;
import org.eclipse.birt.report.model.api.GridHandle;
import org.eclipse.birt.report.model.api.GroupElementFactory;
import org.eclipse.birt.report.model.api.GroupElementHandle;
import org.eclipse.birt.report.model.api.GroupHandle;
import org.eclipse.birt.report.model.api.ImageHandle;
import org.eclipse.birt.report.model.api.LabelHandle;
import org.eclipse.birt.report.model.api.LibraryHandle;
import org.eclipse.birt.report.model.api.ListingHandle;
import org.eclipse.birt.report.model.api.MasterPageHandle;
import org.eclipse.birt.report.model.api.ModuleHandle;
import org.eclipse.birt.report.model.api.ParameterGroupHandle;
import org.eclipse.birt.report.model.api.ParameterHandle;
import org.eclipse.birt.report.model.api.ReportDesignHandle;
import org.eclipse.birt.report.model.api.ReportElementHandle;
import org.eclipse.birt.report.model.api.ReportItemHandle;
import org.eclipse.birt.report.model.api.ResultSetColumnHandle;
import org.eclipse.birt.report.model.api.RowHandle;
import org.eclipse.birt.report.model.api.SlotHandle;
import org.eclipse.birt.report.model.api.StyleHandle;
import org.eclipse.birt.report.model.api.TextItemHandle;
import org.eclipse.birt.report.model.api.ThemeHandle;