Match Case is deliberately greyed out while ticked when you are using Find and Replace. This means that it always matches case there. If you find that it is not, you should report it as a bug.
By the way, there is nearly always a better way to make changes in text instead of Find/Replace. If you are changing spelling, you should always use the Wordlist tool or the right-click option to change the spelling instead of Find/Replace, making sure to review the list of occurrences before taking action. You will find the wordlist change spelling tool much more intuitive about case. And you should make sure make sure to record your decision in the Biblical Terms tool if a term exists for that word.
Blessings,
Shegnada James
Language Technology and Publishing Coordinator, SIL Nigeria
Text Processing Specialist – Complex Script, GPS, SIL Intl
Skype: Shegnada.james.
[Email Removed]
+1 972 974 8146