Don't adjust selected time when changing timezones
When using the date selector, I often enter the time I want to look at first (because it is at the top), and then select the timezone after. After selecting the timezone, the time is automatically adjusted based on the original timezone. I would argue that this is rarely what the user wants, because they explicitly changed the timezone because it was incorrect. I often end up having to revert the auto adjusted time after changing timezones.