Arbortext Command Language > set Command Options > set contextrules
  
set contextrules
set contextrules= { on | off}
This command enables or disables context checking. Note that if you have turned context to “off”, it does not reset when you leave and reenter a document. It remains off until you explicitly turn it on again. Because complex document structures can be difficult to maintain without context checking, PTC recommends that you leave context checking on. on is the default.
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Arbortext recommends that if you have been working with context checking off, you set contextrules to on before you save the document. When context checking is off, it is possible to create a document that is no longer valid SGML and that another system may be unable to read.