Bug 202891 NPE throws out when click on data item in layout[0001]
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/BindingDialogHelper.java
&& ( cmbName.getText( ) == null || cmbName.getText( )
						.equals( "" ) ) )
		{
			dialog.getOkButton( ).setEnabled( false );
			return;
		}
		if ( txtName != null
				&& ( txtName.getText( ) == null || txtName.getText( )
						.trim( )
						.equals( "" ) ) ) 
		{
			if ( dialog.getOkButton( ) != null )
				dialog.getOkButton( ).setEnabled( false );
			return;
		}
		if ( this.binding == null )
		
		{
			for ( Iterator iterator = this.bindingHolder.getColumnBindings( )
					.iterator( ); iterator.hasNext( ); )
			{
				ComputedColumnHandle computedColumn = (ComputedColumnHandle) iterator.next( );
				if ( computedColumn.getName( ).equals( txtName.getText( ) ) )
				{
					if ( dialog.getOkButton( ) != null )
						dialog.getOkButton( ).setEnabled( false );
					this.messageLine.setText( Messages.getFormattedString( "BindingDialogHelper.error.nameduplicate", 
							new Object[]{
								txtName.getText( )
							} ) );