Some version control menu choices, which I have seen before, do not appear. What's wrong?

Some version control menu choices, which I have seen before, do not appear. What's wrong?

    This article is outdated.    

- This doesn't apply to the following versions: 3.2

Some version management functions become unavailable when you create an index (such as Table of Contents) within your document. Menu choices that will no longer appear include:

• Edit -> Changes -> Merge Document
• Edit -> Compare Document

In addition, the 'Compare' button in the 'Versions' dialog (accessed using File -> Versions becomes gray (unusable) when the document contains an index.