allowNull.setEnabled( false );
	private void refreshCheckBoxArea( )	{		if ( dirtyProperties.containsKey( CHECKBOX_HIDDEN ) )		{			isHidden.setSelection( getProperty( CHECKBOX_HIDDEN ) );		}		else		{			isHidden.setSelection( inputParameter.isHidden( ) );		}		if ( !DesignChoiceConstants.PARAM_CONTROL_CHECK_BOX.equals( getSelectedControlType( ) ) )		{			if ( !DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) ) )			{				needSort.setEnabled( true );				if ( dirtyProperties.containsKey( CHECKBOX_SORT ) )				{					needSort.setSelection( getProperty( CHECKBOX_SORT ) );				}				else				{					needSort.setSelection( !inputParameter.isFixedOrder( ) );				}			}			else			{				needSort.setEnabled( false );				needSort.setSelection( false );				checkBoxChange( needSort, CHECKBOX_SORT );			}			if ( DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) )					|| PARAM_CONTROL_LIST.equals( getSelectedControlType( ) ) )			{				allowBlank.setEnabled( true );				allowNull.setEnabled( true );				doNotEcho.setEnabled( true );				if ( dirtyProperties.containsKey( CHECKBOX_ALLOW_BLANK ) )				{					allowBlank.setSelection( getProperty( CHECKBOX_ALLOW_BLANK ) );				}				else				{					allowBlank.setSelection( inputParameter.allowBlank( ) );				}				if ( dirtyProperties.containsKey( CHECKBOX_ALLOW_NULL ) )				{					allowNull.setSelection( getProperty( CHECKBOX_ALLOW_NULL ) );				}				else				{					allowNull.setSelection( inputParameter.allowNull( ) );				}			}			else			{				allowBlank.setEnabled( false );				allowNull.setEnabled( false );			}			if ( DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) ) )			{				doNotEcho.setEnabled( true );				if ( dirtyProperties.containsKey( CHECKBOX_DO_NOT_ECHO ) )				{					doNotEcho.setSelection( getProperty( CHECKBOX_DO_NOT_ECHO ) );				}				else				{					doNotEcho.setSelection( inputParameter.isConcealValue( ) );				}			}			else			{				doNotEcho.setEnabled( false );			}		}		else		{			allowNull.setEnabled( false );			allowNull.setSelection( false );			checkBoxChange( allowBlank, CHECKBOX_ALLOW_BLANK );		}		if ( !DesignChoiceConstants.PARAM_TYPE_STRING.equals( getSelectedDataType( ) ) )		{			allowBlank.setEnabled( false );			allowBlank.setSelection( false );			checkBoxChange( allowBlank, CHECKBOX_ALLOW_BLANK );		}	}