Bug 103291 Group key doesn't support inputting text
Description: Group key doesn't support inputting text Steps to reproduce: 1.Add a table and bind it with data set 2.Add a group to the table: enter a row name in the "Group On:" textbox 3.Save and preview Expected result: Everything is OK Actual result: Error occurs because the group key is added as a string not a expression
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/GroupDialog.java
{
			intervalType.add( intervalChoices[i].getDisplayName( ) );
		}
		intervalType.setData( intervalChoices );
		intervalType.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				intervalRange.setEnabled( intervalType.getSelectionIndex( ) != 0 );
			}
		} );
		
		intervalRange = new Spinner( intervalArea, SWT.NONE );
		intervalRange.setLayoutData( new GridData( GridData.HORIZONTAL_ALIGN_FILL ) );
		intervalRange.setMinimum( 0 );
		intervalRange.setMaximum( Integer.MAX_VALUE );
		intervalRange.setStep( 1 );
	}
	/**
	 * Creates the group area
	 * 
	 * @param parent
	 *            the parent composite
	 */
	private void createGroupArea( Composite parent )
	{
		Composite composite = new Composite( parent, SWT.NONE );
		composite.setLayoutData( new GridData( GridData.FILL_HORIZONTAL
				| GridData.VERTICAL_ALIGN_BEGINNING ) );
		composite.setLayout( new GridLayout( ) );
		Group includeGroup = new Group( composite, SWT.NONE );