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
changeFormat.setEnabled( choiceSet != null );
	}
	private String convertNullString( String str )
	{
		if ( str == null )
		{
			return "";
		}
		return str;
	}
	private boolean containValue( SelectionChoice selectedChoice,
			String newValue, String property )
	{
		for ( Iterator iter = choiceList.iterator( ); iter.hasNext( ); )
		{
			SelectionChoice choice = (SelectionChoice) iter.next( );
			if ( choice != selectedChoice )
			{
				String value = null;
				if ( COLUMN_VALUE.equals( property ) )
				{
					value = choice.getValue( );
					if ( isEqual( value, newValue ) )
					{
						return true;
					}
				}
				else if ( COLUMN_DISPLAY_TEXT.equals( property ) )
				{
					value = choice.getLabel( );