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 = new Combo( composite, SWT.BORDER | SWT.READ_ONLY );
			cmbName.setLayoutData( new GridData( GridData.FILL_HORIZONTAL
					| GridData.GRAB_HORIZONTAL ) );
			cmbName.addSelectionListener( new SelectionAdapter( ) {
				public void widgetSelected( SelectionEvent e )
				{
					String bindingName = cmbName.getItem( cmbName.getSelectionIndex( ) );
					for ( Iterator iterator = getBindingHolder( ).getDataBindingReference( )
							.getColumnBindings( )
							.iterator( ); iterator.hasNext( ); )
					{
						ComputedColumnHandle computedColumn = (ComputedColumnHandle) iterator.next( );
						if ( computedColumn.getName( ).equals( bindingName ) )
						{
							setBinding( computedColumn );
							initDialog( );
							return;
						}
					}
				}
			} );
		}
		else
		{
			txtName = new Text( composite, SWT.BORDER );
			txtName.setLayoutData( new GridData( GridData.FILL_HORIZONTAL
					| GridData.GRAB_HORIZONTAL ) );
			txtName.addModifyListener( new ModifyListener( ) {
				public void modifyText( ModifyEvent e )