I opened the browser and then the mailbox. In the mailbox I goto exit under the file menu and both windows close.

The menu item to close a single window is "Close". "Exit" is actually supposed to close all of the Mozilla windows. I agree that this is confusing (see bug 39057). It's especially bad (compared to other confusing things) because closing more windows than you intended to often means losing data. The solution I prefer is moving the "Close" option to the bottom (right above "Exit") and/or changing "Exit" to "Close All".

This is not just for mail. Changing component to browser. Current behavior is correct as described - Exit should take the user out of the entire application. If the user has a mail compose window or Composer page open, we will prompt the user to save his/her data.

.

The problem is, the *browser* won't tell you if you're going to lose data (a url you don't have memorized or bookmarked, or text typed in a web-based e-mail form). It's very non-obvious that selecting "Exit" in mailnews would close browser windows -- especially since "Close" is nowhere near "Exit". Lchiang, if you need evidence that it's confusing, look at this bug :)

wouldn't a fix for bug 44602 (Need quit-application notification) help this situation?

is bug 44602 a backend or ui thing?

over to UI Design feedback.

See Brendan, it's not just me who thinks that having `Close' and `Exit' apart from each other in the File menu is causing errors ... *** This bug has been marked as a duplicate of 39057 ***

vrfy dup