Though you use a few paragraph and character styles, there is a lot of direct formatting in your document. There are also “logical” flaws in the structure compelling you to manually edit to correct the consequences.
An important factor in degrading performance is related to your images. You have inserted them “as is” and scaled them in Writer. Ideally, images, all the more if they are numerous, should be cropped and scaled in a dedicated program before being imported into Writer so that Writer has nothing to do on them.
Also, all you images are manually positioned, creating severe direct formatting (DF) conditions (these are more serious and stressful than text direct formatting). I know that creating adequate frame styles is really difficult and they are extremely sensitive to DF, to the point that clearing DF is next to impossible unless you apply an unrelated frame style and reapply the desired one.
And you are not consistent with Wrap mode. You seem to have opted (unless it is your default) for Parallel. This is good for images intended to be in the middle of text. But when you want the image to be alone, you compensate with empty paragraphs to avoid text around the image. This is bad. Empty paragraphs always disturb your layout when text is reflown due to edits. A well-structure document should have no empty paragraph (because it contains no information). You should design one frame style per “type” of image: full-width illustration (no text around it), right-side of text, … Configure them with “generic” relative-positioning properties so that you don’t create DF by moving them with the mouse.
Paragraph styles
You start with Default Paragraph Style. This style should never be used for your argumentation. In the tree structure of style inheritance, this style is the ultimate ancestor of all. Its role is to define common attributes shared by all others. I.e. if you configure it for some meaningful paragraph, inheritance will influence other styles, forcing you to compensate, which will also propagate to some others, etc.
You added DF to reach your desired look. DF is always bad. Author’s name is styled Body Text with DF. Again this is faulty.
Since this looks like the title of the document, built-in styles like Title and Subtitle would be the preferred ones. You can create an additional one Author for your name.
You then have a global TOC. You replaced the built-in Contents n styles by Body Text which is the “standard” style for the discourse. You are fortunate enough that your headings are short enough so that the justify property of Body Text does not take control of the line (tab to page numner prevents this).
You are not consistent with the use of character styles. Everything in bold results from a DF.
Remember that a style application does not primarily specify some decoration for your text. From an author’s point of view, styles are a semantic markup of the text emphasising significances: Body Text for the main topic, Heading n for the various outline levels, Emphasis on “special” words, Strong Emphasis on important sequences, … You translate these shades of significance in typographical attributes to convey your points to the reader. Don’t do it the other way round, this makes more difficult to tune the look afterwards.
Document structure
You ruined the standard Heading n architecture to replace it with one of your own without measuring the consequences.
Parts of your book are titled with a Heading paragraph. Heading style plays the same role as Default Paragraph Style for all headings: you configure it for your preferred defaults and they cascade down to all Heading n. Don’t use it for any heading. Otherwise, you must restructure the Heading n family as you did after you noticed adverse effects on your formatting.
Heading n are used for the outlines in your parts, but:
- you removed them from
Tools>Heading Numbering probably because you didn’t know how to set it to cope with your design choice
This turned off automatic heading numbering.
- you offset their “natural” outline level
This is however innocuous.
- you attached them to list style Numbering 1
This is a serious potential error because you’re no longer protected by the reserved property of the internal heading numbering style. If you ever have a numbered list based on the same style in your document, it will interfere with your headings and mess heading numbering.
- you are inconsistent between your Heading n and Numbering 1
You chose to centre your headings but the list style requests specific alignment of the number followed by tabs which only makes sense when heading is left-aligned. When you centre a heading, the only reliable numbering option is left 0cm followed by space or nothing and no indent. Note how the indent on level 2 prevents paragraph background to extend to left margin.
The chapter TOC in part SA1 is styled List instead of the usual Contents n. I understand you want a different look from the global TOC. However, List is a bad choice. Again, this is an “ancestor” for all paragraph styles intended to format list items. Any customisation you make on it influences other styles.
Your “parts” SA n could have been automatically numbered by Heading 1 and Tools>Heading Numbering. You easily remove the number for “Annex” et al. by pressing Bksp at start of the heading where you don’t want a number.
Style dictionary
You completely messed up the factory relationship between styles. This prevents you from tuning your appearance by customising only a few key styles. You must now practically modify every style.
Also you edited your document some time in the past with M$ Word which left “fossils” of its insufficient structuring primitives as numerous character and list styles. Avoid mixed edits, they pollute documents and damage progressively them.
Conclusion
I suppose that the extra indexes you’re talking of are the “chapter TOCs” (Writer has an ambiguous vocabulary in this area because all TOC, tables of figures, tables of …, alphabetical index are generically called indexes).
The crash is probably caused by your reworking of the built-in heading feature (not speaking of the raw images if they number by hundreds). It can be done but you must be very cautious when you don’t master all the subtleties of this advanced usage. Factory settings represent a good compromise. It can be configured with Tools>Heading Numbering but replacing it completely requires super expert guru knowledge.
