Previous versions of OWA didn't let you look at mail headers. In Exchange 2007, you can. Open a message in OWA by double-clicking on it or hitting Enter, then click on the "Message Details" icon.
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Updated Jul 01, 2019
Version 2.0
Blog Post
Hi folks,
I'm glad you like having access to message headers, even if it isn't always convenient. We considered making the dialog box resizable. There a couple of issues with it:
1. none of our other dialogs are resizable (not the best reason)
2. it would be a significant amount of work, and we felt that we would be better off investing our efforts in features that would see more usage. Let's be honest, message headers are something that most users don't care about. You and I like having access to them, but most users don't understand what they mean.
Going forward with OWA, we'll definitely see if there's something better we can do. If we can't make the dialog resize, what would make it easier for you to use headers? I can't promise that we'll add this feature to OWA Light, but it's something that we'll consider.
I'm glad you like having access to message headers, even if it isn't always convenient. We considered making the dialog box resizable. There a couple of issues with it:
1. none of our other dialogs are resizable (not the best reason)
2. it would be a significant amount of work, and we felt that we would be better off investing our efforts in features that would see more usage. Let's be honest, message headers are something that most users don't care about. You and I like having access to them, but most users don't understand what they mean.
Going forward with OWA, we'll definitely see if there's something better we can do. If we can't make the dialog resize, what would make it easier for you to use headers? I can't promise that we'll add this feature to OWA Light, but it's something that we'll consider.