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
tocArea.setLayout( UIUtil.createGridLayoutWithoutMargin( 2, false ) );
		
		tocEditor = new Text( tocArea, SWT.SINGLE | SWT.BORDER );
		tocEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		Button exprButton = new Button( tocArea, SWT.PUSH );
		exprButton.setText( "..." ); 
		exprButton.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent event )
			{
				ExpressionBuilder expressionBuilder = new ExpressionBuilder( tocEditor.getText( ) );
				expressionBuilder.setExpressionProvier( new ExpressionProvider( dataSetList ) );
				if ( expressionBuilder.open( ) == OK )
				{
					tocEditor.setText( expressionBuilder.getResult( ) );
				}
			}
		} );
	}
	/**
	 * Creates the title area
	 * 
	 * @param parent
	 *            the parent composite
	 */
	private void createTitleArea( Composite parent )
	{
		int margins = 2;
		final Composite titleArea = new Composite( parent, SWT.NONE );
		FormLayout layout = new FormLayout( );
		layout.marginHeight = margins;