I used to be able to set columns in mail when using the column layout feature. Now there doesn't appear to be a way to do this - also is it possible to rearrange the columns showing in mail other than turning a column off?
I started this thread and so will save you some time paging through the hundreds of replies: there is no workaround, Apple has said nothing, and the two most common mail apps that folks are migrating to get columns is Thunderbird and Outlook, both of which have improved and are more Apple friendly.
I have a different take on why. Columns still exist in every other OS function in Finder and elsewhere. Code like this are 'objects' that can be dropped into most other apps, so I do not believe it is lack of willingness to 'support the code'.
I do think they are trying to move the Mac OS to as close as possible to the iPhone/ipad OS to make the user experience nearly the same. But this makes for a big dumbing down of the Mac OS.
The mystery to me is that you can't change column width in iPhones-- so are they now going to remove the ability to do that in ALL Mac OS apps, finder etc.? I highly doubt that, so why selectively remove it from Mail?
I think they don't believe it is that popular so why not get rid of it. Hence the importance of letting our voices be heard.
Column width in mail for OSX Catalina
