When you start a new calendar event and it opens in a new window, the menu bar at the top includes an "Options" menu which includes features like "Show Timezones."
However, if you go to Tools > Settings > Calendar to check the box for "Edit events and tasks in a tab instead of in a dialog window" then start a new event, there is no "Options" menu available, and thus you can not enable the "Show Timezones" feature.
This is something I noticed in version 102.8.0 64-bit for Windows. Please let me know if I am overlooking something, or if I should report this as a bug in Bugzilla.
