Bug 390669 [Accessibility]Press 'Tab' doesn't focus on the next report item when adding relative period aggregation.
xtab/org.eclipse.birt.report.item.crosstab.ui/src/org/eclipse/birt/report/item/crosstab/internal/ui/dialogs/CrosstabBindingDialogHelper.java
import org.eclipse.birt.report.item.crosstab.core.de.DimensionViewHandle;
import org.eclipse.birt.report.item.crosstab.core.de.LevelViewHandle;
import org.eclipse.birt.report.item.crosstab.core.util.CrosstabUtil;
import org.eclipse.birt.report.item.crosstab.internal.ui.editors.model.CrosstabAdaptUtil;
import org.eclipse.birt.report.model.api.AggregationArgumentHandle;
import org.eclipse.birt.report.model.api.CalculationArgumentHandle;
import org.eclipse.birt.report.model.api.ComputedColumnHandle;
import org.eclipse.birt.report.model.api.Expression;
import org.eclipse.birt.report.model.api.ExpressionHandle;
import org.eclipse.birt.report.model.api.ExpressionType;
import org.eclipse.birt.report.model.api.ExtendedItemHandle;
import org.eclipse.birt.report.model.api.IResourceLocator;
import org.eclipse.birt.report.model.api.ModuleHandle;
import org.eclipse.birt.report.model.api.ReportItemHandle;
import org.eclipse.birt.report.model.api.StructureFactory;
import org.eclipse.birt.report.model.api.activity.SemanticException;
import org.eclipse.birt.report.model.api.elements.DesignChoiceConstants;
import org.eclipse.birt.report.model.api.elements.structures.AggregationArgument;
import org.eclipse.birt.report.model.api.elements.structures.CalculationArgument;
import org.eclipse.birt.report.model.api.elements.structures.ComputedColumn;
import org.eclipse.birt.report.model.api.extension.ExtendedElementException;
import org.eclipse.birt.report.model.api.metadata.IChoice;
import org.eclipse.birt.report.model.api.metadata.IChoiceSet;
import org.eclipse.birt.report.model.api.olap.CubeHandle;
import org.eclipse.birt.report.model.api.olap.DimensionHandle;
import org.eclipse.birt.report.model.api.olap.LevelHandle;
import org.eclipse.birt.report.model.api.olap.MeasureGroupHandle;
import org.eclipse.birt.report.model.api.olap.MeasureHandle;
import org.eclipse.birt.report.model.elements.interfaces.ICubeModel;
import org.eclipse.jface.layout.GridDataFactory;