I have to curate and compile sheets of announcements for a local humanitarian service provider forum. I do this by sifting through my Office 365 emails, and double clicking those that contain announcements so they open a window, then sorting the windows on a second screen, then read them, summarize them, file the pertinent information with links for my summaries, and when I get a page of them, send them out. I usually start with about 15 announcements on my other screen, and it takes me some time to get them all sorted and cascaded in order for the curation. Some of them link to PDFs which Office 365 doesn't always preview and I click download, and this used to open them in the main browser window in a new tab, where I could read them and then save them. Recently, this behavior changed and they now open right in the window the email is in, with no bars of any kind or tabs to get out of them again. I hit the stack of pancakes button, and it had a tab marked Exit, so I thought that would exit me from the view. Instead, counterintuitively, it exited me completely from FireFox, closing all of my carefully cascaded windows of announcements, and my main browser window with Office 365 in it and everything else. Thanks a bunch. 1) What was so wrong with the previous setup that you needed to change it? 2) How for the love of whatever the author of this new "feature" was smoking, do I get it to revert to the email or is opening these attachments by "download" no longer possible without punting the whole thing to exit? 3) Does this mean I need to permanently disallow Firefox as the browser for all my PDFs or is there some way of doing something non-fatal to my work on a per-boot basis?