When I type ā\ cā, the agenda view limits to my (c)all tags. This is what I expected to see.
When I type ā\ <space>ā, however, it limits to every tag *but* the empty tag. This is the opposite of what I expect to see. Emacs : GNU Emacs 28.2 (build 1, x86_64-apple-darwin22.5.0, Carbon Version 169 AppKit 2299.6) Package: Org mode version 9.6.4 (release_9.6.4-1-g76cf21 @ /Users/johnw/.emacs.d/lisp/org-mode/lisp/) -- John Wiegley GPG fingerprint = 4710 CF98 AF9B 327B B80F http://newartisans.com 60E1 46C4 BD1A 7AC1 4BA2