@
theducks and
davidfor - syntaxes all of us, so I prefer to fill in the form - see attachment
Chris_Snow - hit the blue button in Prefs->Custom Column with the 'i' to change the names
the value of the blank in a three value yes/No column is 'empty' as in
Code:
not #in_reading_list:"empty" - i.e. then it must be Y or N
#in_reading_list:"empty" - i.e no value, blank, null
BR