Bug 180864 Change Allow Null option in Cascading Group.[0705]
Description: Change Allow Null option in Cascading Group. Build number:2.2.0.v20070404 Steps to reproduce: 1. New a cascading group and add sub parameter. Expected result: Is Required option in cascading group definition dialog. Actual result: Allow null value option in Cascading Group definition dialog Error log:N/A
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
} );
		listLimit.addModifyListener( new ModifyListener( ) {
			private String oldValue = ""; 
			public void modifyText( ModifyEvent e )
			{
				try
				{
					if ( !StringUtil.isBlank( listLimit.getText( ) ) )
					{
						Integer.parseInt( listLimit.getText( ) );
						oldValue = listLimit.getText( );
					}
				}
				catch ( NumberFormatException e1 )
				{
					ExceptionHandler.openErrorMessageBox( ERROR_TITLE_INVALID_LIST_LIMIT,
							MessageFormat.format( ERROR_MSG_INVALID_LIST_LIMIT,
									new Object[]{
										Integer.toString( Integer.MAX_VALUE )
									} ) );
					listLimit.setText( oldValue );
				}
			}
		} );
		new Label( limitArea, SWT.NONE ).setText( LABEL_VALUES );
		allowNull = new Button( composite, SWT.CHECK );
		allowNull.setText( BUTTON_ALLOW_NULL_VALUE );
		allowNull.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		allowNull.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )