Hover your cursor over the addresses. Hopefully a pop-up tooltip thingy will appear listing the addressees.

It's become difficult to see, but if you move the cursor about slowly in the grey area between the addresses and the message text window, you should be able to find the handle that lets you resize the addressing area and thereby see more addresses. Mine reveals its presence by changing to a slightly paler shade of grey.

I do detest the near-zero discoverability in modern GUI design. We seem to be slavishly copying of all the worst features of the Google UI.  :-(

Raggedy said

It's difficult to check whether I've entered all of several intended recipients of an email I'm composing. I can scroll up and down, but I can't see the entire list to check for inclusions and duplicates. Please reinstate the pull-down arrow!

Zenos said

Hover your cursor over the addresses. Hopefully a pop-up tooltip thingy will appear listing the addressees. It's become difficult to see, but if you move the cursor about slowly in the grey area between the addresses and the message text window, you should be able to find the handle that lets you resize the addressing area and thereby see more addresses. Mine reveals its presence by changing to a slightly paler shade of grey. I do detest the near-zero discoverability in modern GUI design. We seem to be slavishly copying of all the worst features of the Google UI.  :-(

Got it! Thanks so much. A little more detail for the benefit of others: you'll find the addressing area resize handle immediately above the white text area, in the narrow part of the grey area below all of the address field, subject line, scroll boxes and icons.