Why didn't my preference appear in PerfectIt?

The usual causes, in order of likelihood:

1. It's under a regular heading, not a Preferences List heading. Only sections under Preferences List headings (the ones with the green button) are exported to PerfectIt. Regular headings (Heading 1, 2, 3) are for material that stays in Styleworks.

2. The info bar is red. Unknown terms can't be exported until you add the search term — see Why has the info bar gone red?

3. It's a private annotation. Anything after // never goes to PerfectIt.

4. The export hasn't reached PerfectIt yet. On Mac, your style appears the next time you open PerfectIt. On Windows, you need to import the downloaded file via Manage Styles › Import.