If you right click in the folder list in OWA (only available in the “rich“ client which is IE5+), one of the options is “Open in New...“. You might ask - why not just add the word “Window“? There's plenty of space. What's the deal?
The deal is that IE5 didn't allow this menu to pop-over outside of the navigation pane (with the folder list in it), so we had to keep the text short enough to fit. English would have fit in just fine with the word “window“ there, but what about other languages like French?
Those French folks are a lettery bunch (even moreso than German in this case... although only by one letter). So why not just make the English string “open in new window“ and make the other languages where the localized string is too long the translation of “open in new...“? Well, the reason is that... that would be a real pain in the butt. We'd have to hold the hands of the localizers and it would just end up creating more work than it's worth, and then we'd probably run into some browser/language/resolution/operating system combination where it didn't work as expected.
A lot of thought goes into some of the seemingly smaller things. We actually spent a fair amount of time tweaking that menu. I remember one debate we had about the “Update folder” option on this menu. It updates the unread count in the folder list for that folder - it does not update the list of messages. We went back and forth between “Refresh folder” and “Update folder”, trying to find an option that would make the purpose most obvious. And whatever we came up with had to keep in mind the localization of the string of course.
P.S. pop-over works fine in IE6.