Restart TB
   In the 'Find events pane' select 'All events'
   Click on the head of the title column to sort by title
   check if there are any events without a title at the start of the list (or was it the end?)
   remove all events without a title or set a title
   Searching should now work

https://bugzilla.mozilla.org/show_bug.cgi?id=1919677 behandeld dit probleem en daarin staat een mogelijke oplossing om dit probleem zelf op te lossen. Restart TB In the 'Find events pane' select 'All events' Click on the head of the title column to sort by title check if there are any events without a title at the start of the list (or was it the end?) remove all events without a title or set a title Searching should now work