Arbortext Editor constantly enforces the defined document structure rules by checking context interactively while you edit the document, not permitting you to insert elements or text at invalid locations. Since context checking is usually on, Arbortext Editor makes sure you are creating a valid document as you write so you need not worry about creating a structurally invalid document. The Arbortext Editor context checker keeps you from inserting markup (such as elements and entities) and text in places where it is not permitted by your document's document type.

At points, some documents may be ambiguous or incomplete according to the rules of your document type. Arbortext Editor allows this incompleteness temporarily to make document creation easier. For example, a document might be missing a required element such as an appendix. Because the appendix goes at the end of the document, a missing appendix does not interrupt context checking, since it does not affect the context of other elements. Such documents may be saved, but are flagged as incomplete with an INC indicator on the status bar. They are still valid files.

Arbortext Editor allows incomplete documents so that authors are not forced to fix everything before a save. Your workflow can be flexible because you (or others) can complete the document structure at a later time. Typically, the author assembles the document and may leave out some components temporarily, or leave them to be assembled by others. When the document components are fully assembled, or when you want to see what work remains, a completeness check can be done.

When context checking is on (the default mode of operation), the Insert Markup dialog box shows only the elements and other constructs that are permitted at the current cursor location. When the context checker indicates incorrect context, invalid menu options are unavailable. The context checker provides error messages if you try to cut or to insert text in any way not permitted by the document type.

Arbortext Editor prevents insertion of invalid markup only when context rules are turned on. You can turn off context checking by clearing the Tools > Context Rules check box. This can be useful if you want to insert a file anywhere in a document and then fix the tags after the file is inserted. To ensure that you still have a valid file, choose Tools > Context Rules again to check the check box and turn context rules on again.