To the right of the two time-setting boxes, there is a picture of a chain link. This is a button and if clicked, will toggle on/off the linking of the two buttons. By default they are linked and whichever you change, the other will track to preserve the default event period.

Thank you for that, it's been driving me spare!

It's a shame nobody bothered to update the "How to" page ([https://support.mozilla.org/en-US/kb/creating-a-new-event-or-task] ) to reflect this change. And a bit poor to set a new feature to the new default without explaining it.

It would be nice if somehow the appearance of the chain would indicate whether the times are linked. Perhaps an open link could mean that you could change the times independently.

Did you not see the arrowhead that comes and goes to indicate when they are linked or not?

To be fair, the arrowhead only "comes and goes" if you know to click on the chain - there's nothing to make it obvious to suggest that it's anything more than decorative. I note that the help page (as linked to in my reply of 19/10) still hasn't been updated to reflect the change- the graphics there don't show the chain and arrow(s). I still don't see why this change was imposed on long-standing users of Lightning with no notice...

Sorry, I did not notice the change at first, my eyes are not as young as they used to be.

Zenos said

Did you not see the arrowhead that comes and goes to indicate when they are linked or not?