Why do I Have to Click Twice to Open Catalina Mail

Barney, Peter, I think you are trying to help but this isn't really...

At least one of us (i.e. Me) that discussed a very particular issue (the subject of this thread, specifically Mail) have reported it as an undocumented change that does not necessarily support users that were used to the original functionality, especially given the original functionality was more in line with the operation of other Apps.

Apps that have no function when the last document window is closed should auto-quit when you close that document window.

Apps that have a function even when all windows are closed should not auto-quit. It’s been that way for about two decades.

(cough) Safari (cough) hasn't worked this way for about two decades

But we were only asking about why Mail seems to have changed, so if anyone wants to start a new thread on whatever subject we are now onto...

I was having this issue as well. I resolved it by removing the Mail icon form the dock, and then re-adding the Mail Icon to the dock. After that, Mail window opened with one click on the Mail icon in the dock.

I recently raised this issue with the senior tech support associate at our local Apple store. Despite numerous assertions on this forum that the problem with the observation many of us have reported here is that we just don't understand the process, this Apple tech advised in no uncertain terms that two clicks or double-click to open Mail (both work) is NOT normal, consistent, or intended behavior and will likely be corrected in an upcoming Catalina revision.

The pined solution is exactly what is going on. It is a Catalina Mail app slight change in user interface dedign that affects all Macs alike running Catalina and some other apps (but not all) behave the same way

You cannot change it. No need to keep trying.

Just goes to show you. I installed Catalina on 5 of my Macs and it doesn't do it on any of them.

Same exact issue here on 2017 IMac, need to double click Mail to open.

FWIW, you seem to have hit the nail on the head. If I close the Mail window then quit Mail, It will open with the window still closed. Something it never occurs to me to do.

Not defending, but belittling, yes.

Dropping £50 worth of Aperture, obsoleting DVD or making MBP's non upgradeable now there's something to complain about, but it made no difference.

Yes, it is normal for most apps.

Don’t close the message viewer before quitting the app.