Bug 136241 [regression]Preview template in web viewer and pdf didn't get correct effect.
Description: Preview template items in web viewer and pdf didn't get correct effect. Steps to reproduce: 1. Create template items. 2. Preview in Web Viewer and pdf. Expected result: Same effect as in html. Actual result: In web viewer, see only blank box. In pdf, blank page.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/command/ContentCommand.java
boolean unresolveReference, boolean flag ) throws SemanticException
	{
		doRemove( content, slotID, unresolveReference, flag );
	}
	/**
	 * @see #remove(DesignElement, int, boolean)
	 * @param content
	 *            the element to remove
	 * @param slotID
	 *            the slot from which to remove the content
	 * @param unresolveReference
	 *            status whether to un-resolve the references
	 * @param flag
	 *            Use the flag to indicate whether this method is do with the
	 *            element itself or do with its contents.
	 * @throws SemanticException
	 *             if this content cannot be removed from container.
	 */
	private void doRemove( DesignElement content, int slotID,
			boolean unresolveReference, boolean flag ) throws SemanticException
	{
		assert content != null;
		
		if ( !element.getDefn( ).isContainer( ) )
			throw new ContentException( element, slotID,
					ContentException.DESIGN_EXCEPTION_NOT_CONTAINER );
		ContainerSlot slot = element.getSlot( slotID );
		if ( slot == null )
			throw new ContentException( element, slotID,
					ContentException.DESIGN_EXCEPTION_SLOT_NOT_FOUND );