ITextVersion::ReiteratedVersionNumber Property
Gets the oldest version number for which all text changes between that version and this version have been canceled out by corresponding undo/redo operations.
Assembly: Microsoft.VisualStudio.Text.Data (in Microsoft.VisualStudio.Text.Data.dll)
If this property is not the same as VersionNumber, then for every ITextChange not originated by an undo operation between ReiteratedVersionNumber and VersionNumber, there is a corresponding ITextChange originated by an undo operation that cancels it out. So the contents of the two versions are necessarily identical.
Setting this property correctly is the responsibility of the undo system; aside from this property, the text buffer and related classes are unaware of undo and redo. The ITextVersion objects created through CreateReadOnlyRegionEdit or ChangeContentType have no text changes and will therefore keep the ReiteratedVersionNumber of the previous version.