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/ParameterDialog.java
{
			valueTable.refresh( );
			updateTableButtons( );
		}
	}
	private boolean getProperty( String key )
	{
		return ( (Boolean) dirtyProperties.get( key ) ).booleanValue( );
	}
	private String format( String string )
	{
		if ( canBeNull( ) && string == null )
		{
			return LABEL_NULL;
		}
		if ( StringUtil.isBlank( string ) || formatCategroy == null )
		{
			return string;
		}
		try
		{
			String pattern = formatPattern;
			if ( formatPattern == null )
			{
				if ( DesignChoiceConstants.STRING_FORMAT_TYPE_CUSTOM.equals( formatCategroy )
						|| DesignChoiceConstants.DATETIEM_FORMAT_TYPE_CUSTOM.equals( formatCategroy )
						|| DesignChoiceConstants.NUMBER_FORMAT_TYPE_CUSTOM.equals( formatCategroy ) )
				{
					return string;
				}