thanks, I think I got it now…the main problem was that it is highlighting the first occurrences of single words not phrases (I also noticed that I can modify the Minimum word length).
So here comes my second question – is it possible to highlight the entire phrase only not singe words since it could be misleading?
For example in here: https://imgur.com/ZvwxrDV
The phrase “test a” is not highlighted for the results marked with #1 and #2 since the phrase is probably somewhere deeper in the article.