The issue:

When viewing a mail folder (e.g. inbox, other folder, etc.) and you're working your way through a long list of mail to read, and thus have scrolled down through the long list, if you open another mail tab view (e.g. click on a sender's name and it opens a new tab with all that sender's mail), and then return to the original tab view, the scroll status has been lost and you are back at the top of the long list of mail, requiring you to scroll all the way back down to where you were.  A nuisance and workflow hinderance.

The requested solution:

Preserve the scroll state in all mail tab views, so that you can switch between tabs and not lose the scroll states in each tab.