About Arbortext Styler > Defining Page Layout > Page Layout Overview > Nested Page Sets
  
Nested Page Sets
As a general rule, PTC Arbortext publishing will process nested page sets. If you are using the XSL-FO engine, however, you should note the following:
Nested page sets are not valid under the XSL-FO specification, although the publishing process will attempt to handle them.
In some rare cases, the results using nested page sets will be slightly different to those provided by a flat page set arrangement, because of the way in which XSL-FO property inheritance works.
Arbortext Styler will attempt to flatten a nested page sequence when publishing via the XSL-FO engine. Flattening the sequence adds a non-trivial amount of time to the publishing process and may provide unexpected results in output, for example numbering sequences may not continue as required or unnecessary blank pages may appear.
You may see these differences in print, PDF or RTF outputs.
To avoid this situation, you may wish to reconfigure your page sets to ensure they are not nested. Select XSL-FO as the effective print engine, then click Tools > Validate Page Sets. Select the Require XSL-FO compliance option to indicate which page sets do not confirm to the XSL-FO specification as they are nested.