Bug 122850 Table/list should not be able to be inserted in Master Page mode.
Description: Table/list should not be able to be inserted in Master Page mode. Steps to reproduce: 1. New a report and transfer to Master Page mode. 2. New a datasource and dataset 3. Drag a list/table to page header/footer, bind it to dataset and drag some columns inside. 4. Save and preview Expected result: Insert list/table item in master page should be forbidden. Actual result: They are allowed and preview showed "undefine" in page
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/validators/TableHeaderContextContainmentValidator.java
private final static TableHeaderContextContainmentValidator instance = new TableHeaderContextContainmentValidator( );
	/**
	 * Returns the singleton validator instance.
	 * 
	 * @return the validator instance
	 */
	public static TableHeaderContextContainmentValidator getInstance( )
	{
		return instance;
	}
	/**
	 * Validates whether the given element can recursively resides in the
	 * specific slot of specific container type.
	 * 
	 * @param module
	 *            the module
	 * @param element
	 *            the element to validate
	 * 
	 * @return error list, each of which is the instance of
	 *         <code>SemanticException</code>.
	 */
	public List validate( Module module, DesignElement element )
	{
		if ( !( element instanceof ListingElement ) )
			return Collections.EMPTY_LIST;
		return doValidate( module, element, DesignElement.NO_SLOT );
	}
	/**
	 * Checks whether the <code>toValidate</code> is or is in the table