I have prepared a NSSpellServer spelling and grammar checker for Slovenian proofing in macOS. My proofing service gets used when I explicitly set keyboard spelling language to "Slovenian (Besana)" (my proofing service).
However, no matter how I set the Check Grammar With Spelling option or Check Grammar checkbox in the TextEdit.app or Mail.app, my proofing service does not get any request for grammar checking.
I am supporting checkString call for Unified checking and checkingTypes never contains NSTextCheckingTypeGrammar flag. When using legacy API before Unified checking support, the checkGrammarInString is never called either.
If I do the grammar regardless the checkingTypes parameter, the app shows grammar mistakes correctly. But that is bad UX. Need to follow user demand for with grammar or without grammar.
I don't know what am I doing wrong? On my home iMac v11 it actually works. No idea what I did there to make it work. Just worked. On my working Mac Mini v13 it won't check grammar. On another MacBook Pro v15, it won't check grammar either.
Apps do check spelling with my proofing service. But not grammar. Same apps do grammar checking with stock AppleSpelling.service just fine.
I have checked my Info.plist, using Hardened Runtime, have empty Entitlements, to no avail.
Was there some new grammar API introduced after macOS v11 Big Sur, I should implement? Is there some specific Entitlement, signature, notarization I should perform to get going? Some documentation I am missing?