Spellcheckers marking words with possessive apostrophes

Factual Questions
1

Why do word processor spellcheckers recognise a word in its dictionary, but if it has a possessive “apostrophe s” it doesn’t recognise it and it needs to be added to the dictionary as a separate entry?

Example:
“Frank has a broken toy” = needs to be added
“Frank’s toy is broken” = needs to be added as a separate entry

What’s up with common english usage not being accepted in a spellcheck dictionary?

2

In world where people stack box’s of CD’s on table’s, we should give thank’s that Microsoft Word err’s on the side of caution. FWIIW, Textpad automatically accepts an apostrophe-s after a word once it has been added to the dictionary (even in the same spell check session).