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
}
	
	protected boolean initDialog( )
	{
		cascadingNameEditor.setText( inputParameterGroup.getName( ) );
		promptTextEditor.setText( UIUtil.convertToGUIString( inputParameterGroup.getPromptText( ) ) );
		if ( DesignChoiceConstants.DATA_SET_MODE_MULTIPLE.equals( inputParameterGroup.getDataSetMode( ) ) )
		{
			multiDataSet.setSelection( true );
		}
		else
		{
			singleDataSet.setSelection( true );
		}
		valueTable.setInput( inputParameterGroup );
		refreshParameterProperties( );
		updateButtons( );
		return true;
	}
	
	protected void okPressed( )
	{
		try
		{
			saveParameterProperties( );
			inputParameterGroup.setName( UIUtil.convertToModelString( cascadingNameEditor.getText( ),
					true ) );
			inputParameterGroup.setPromptText( promptTextEditor.getText( ) );
			if ( isSingle( ) )
			{