Bug 182673 No default value error message prompts incorrectly
Steps to reproduce: 1. New a report parameter; 2. Choose control type as Combo; 3. Choose parameter as dynamic type; Expected result: As the isRequired is false by default, parameter's default value can be null value. There should be no error message about no default value prompt. Actual result; Error messages prompts
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
isRequired.setSelection( inputParameter.isRequired( ) );
		doNotEcho.setSelection( inputParameter.isConcealValue( ) );
		needSort.setSelection( !inputParameter.isFixedOrder( ) );
		changeDataType( );
		dataTypeChooser.setText( DATA_TYPE_CHOICE_SET.findChoice( inputParameter.getDataType( ) )
				.getDisplayName( ) );
		switchParamterType( );
		loading = false;
		return true;
	}
	private void initValueArea( )
	{
		if ( isStatic( ) )
		{
			if ( DesignChoiceConstants.PARAM_CONTROL_CHECK_BOX.equals( getSelectedControlType( ) ) )
			{
				if ( isValidValue( defaultValue ) != null )
				{
					defaultValue = null;
					defaultValueChooser.select( 0 );
				}
				else
				{
					if ( Boolean.valueOf( defaultValue ).booleanValue( ) )
					{
						defaultValueChooser.select( 1 );
					}
					else
					{
						defaultValueChooser.select( 2 );