[TYPO3-ttnews] Override categorySelection from page tsconfig?

[Jacob Roe]

I have followed docs example to setup xml feeds:
https://docs.typo3.org/typo3cms/extensions/tt_news/ExtNews/Configuration/XmlFeedsFromTtNews/

I want to show different category for each page so I set this in page TSConfig:
    xmlnews.10.categoryMode = 2
    xmlnews.10.categorySelection = 5

But it makes no change. In root template I have set
    xmlnews.10.categoryMode = 0
which overrides all.