Specifically, the Wall Clock Time format setting will only show up when you pan the capture all the way to the left (i.e. at the beginning of the capture).
When you are zoomed in anywhere else in the capture, the wall clock time will not appear. This might cause confusion and make the setting seemingly appear to not do anything.
More information below on this behavior and how to work around it:
We need to improve how we activate this setting, such that it doesn't appear to not work.