Bug 153523 OK button in parameter dialog is enabled without default value in combo-box
Description: OK button in parameter dialog is enabled without default value in combo-box Steps to reproduce: 1. New a report parameter, combo-box. 2. Click New button, input abc as value, click OK 3. Set abc as default value and close Edit Parameter dialog. 4. New a data source and dataset 5. Edit the parameter, remove abc value and import values from dataset Expected result: OK button is disabled for there is no default value. Actual result: OK button is enabled.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
} );
		multiDataSet = new Button( composite, SWT.RADIO );
		multiDataSet.setText( RADIO_MULTIPLE );
		multiDataSet.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				refreshValueTable( );
				updateButtons( );
			}
		} );
	}
	private void createDynamicParamsPart( Composite parent )
	{
		Composite comp = new Composite( parent, SWT.NULL );
		comp.setLayout( UIUtil.createGridLayoutWithoutMargin( ) );
		comp.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		Label label = new Label( comp, SWT.NULL );
		label.setText( LABEL_PARAMETERS );
		table = new Table( comp, SWT.FULL_SELECTION
				| SWT.HIDE_SELECTION
				| SWT.BORDER );
		GridData data = new GridData( GridData.FILL_HORIZONTAL );
		data.heightHint = 100;
		table.setLinesVisible( true );
		table.setHeaderVisible( true );
		table.addKeyListener( new KeyAdapter( ) {
			public void keyReleased( KeyEvent e )
			{
				
				if ( e.keyCode == SWT.DEL )