Using ZWNJ ZERO WIDTH NON-JOINER in practice

[James Kass]

On 2021-05-28 7:04 AM, Jukka K. Korpela via Unicode wrote:
> And it is typical intended use for ZWNJ to break a character pair so that
> a ligature is not used for.

Exac‍tly.

di‌stinctive ⇐ ZWNJ between i-s pair

But it should not be typical for the ZWNJ insertion to break spell 
checking.  Yet Mozilla Thunderbird error flags English words with either 
ZWNJ or ZWJ insertions.  (The word "Exactly" above has a ZWJ between the 
c-t pair.)