Document Editor provides content control preservation support (i.e.) Content control present in the input document is preserved upon saving.
Content controls can be categorized based on its occurrence in a document as follows,
InlineContentControl: Among inline content inside, as a child of a paragraph. BlockContentControl: Among paragraphs and tables, as a child of a Body, HeaderFooter.
Note: Content control with custom XML mapping of file type WordML is converted as normal Rich Text Content Control to provide lossless round-tripping upon saving.