Today while using TM (version 2.0.19 on macOS 10.15.7), I noticed that the title case style doesn't seem to work for words of three letters or less that are not conjunctions or prepositions. I wanted to convert a sentence to title case with the Crtl + Opt + U keys and in the sentence the three letter word 'use' didn't become upper case while the longer words did. It appears that conjunctions and prepositions become title case only for four letter words or longer. Is there a particular style that title case adheres to in TM? The two main style types listed on Wikipedia are the AP style and the Chicago style. Does TM use something different?

Title case - Wikipedia