Short version: Can anyone send me a guide that gives a really detailed description of how formatting works in Word? All the hidden mark-ups, stuff where I might need to dig into the XML of a .docx file in order to really understand it.

Long version: I'm working on a tool that takes a big Word document as a template, cuts out sections that aren't relevant to the final document I'm making, and spits a Word document back at me with the sections removed. However, I'm having persistent problems with the formatting of the text being incorrect immediately after a removed section. This has not been a problem in previous versions of this, and the third-party program has not changed, so I'm thinking that this is probably a problem with my formatting of the "template" Word document.

What seems to happen is that after a section is removed, the format will jump to something else. For example, I'll be writing a section where everything is in 11pt indigo-coloured font, and then after a small section is removed, it'll jump to 12pt black font(which is the document's default) until the end of the paragraph. At that point, the correct formatting will take over again.

The most complex instance of the problem is as follows: In the original Word document, there's the following text line-by-line:
(1pt white text tag, defining the end of the section which is being removed)
(8pt blank line)
(14pt black header-formatted text, with some parts highlighted)
(11pt blank line)


(11pt white text with dark red highlight, followed by 11pt white text with red highlight)

The following is what results after the removal:
(8pt blank line)
(14pt white header-formatted text, with some parts highlighted)
(11pt blank line)
(1pt white text with dark red highlight, followed by 11pt white text with red highlight)

The formatting of the removed section is carrying through in ways I do not understand, and that's causing issues with the final product. This is supposed to generate documents that go to our best clients, and the tool that creates them has to be used by my whole department, so it can't have issues like this when my updates are going live.

Thank you.

It isn't unusual at all that formatting reverts back to the document defaults. This wouldn't happen, though, if formatting had been customized properly from the start. For example, you can create one or more paragraph styles that provides formatting which should be different from the document default.

It is up to the creator of the third-party program to ensure that it continues to be compatible with newer versions of Word.

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

How would I go about updating the document to properly use those paragraph styles? Note that this document is about 400 pages long, so any automated tools for fixing it up would really be appreciated, and recreating it from scratch is not practical(there's a lot of security and macros which are managed by different departments, so I can't mess with those).

Sorry, I know this one's a bit hairy.

You can change the document defaults yourself in the Manage Styles dialog box. However, whether that helps in this particular situation depends a lot on what the third-party program actually does.

__________________
Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional

Long story short, there's a lot of XML-style tags embedded in the original Word doc(about 3500 of them). The relevant part of the other program reads these tags, then allows us to check off boxes saying which sections we want to keep and which we want to remove. If a section isn't checked off, it'll cut out the section from <Begin Section> to <End Section>. Otherwise, it'll strip the tags away and keep the text inside them.

The problems are always cropping up after a section is removed. If I had to guess I'd wager that a formatting definition is inside the removed text and that it's being removed, so Word is reverting to the default formats, but that's just a guess from my general computer knowledge, and I don't have enough understanding of the intricacies of Word formatting to feel confident that I have it right.