search engine

Answer to question in item 2: Yes, this is a side-effect of the
set-oriented query-system. (This may change slightly in the future due
to some related space/time optimizations, but this is still uncertain.)

Note that it would be different if you had, e.g., first used “Find
Messages ▸ From or To “xyz”” and then done a search for unquoted
body text. Internally, the two cases would differ like this (simplified
a bit):

$Msgs.filter(from = 'xyz' or to = 'xyz' or #unquoted ~ 'abc')
$Msgs.filter(from = 'xyz' or to = 'xyz').filter(#unquoted ~ 'abc')

With regard to the second point: I find that I mostly want to find the
message which originally used the word I am searching for and not any
replies or forwards with the same word (in which it is quoted), but it
is also a question of efficiency. It is simply slower to search both and
therefore I do not encourage it. When search speed (of unquoted/quoted
text) has been improved then I may change this to make it easier. I like
your suggestion for a single Body Text item with options.

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