+Implement "notmuch search --exclude-threads=<search-terms>" to allow
+for excluding muted threads, (and any other negative, thread-based
+filtering that the user wants to do).
+
+Fix "notmuch show" so that the UI doesn't fail to show a thread that
+is visible in a search buffer, but happens to no longer match the
+current search. (Perhaps add a --matching=<secondary-search-terms>
+option (or similar) to "notmuch show".)
+