Note: Because BeMail messages are used universally by all BeOS mail clients, this tip applies whether you’re using BeMail or another application.
E-mail programs on most platforms let you change the subject line of a stored message, which is really important when you want to file messages in folders for long-term storage and future reference. Unfortunately, the BeMail Subject: attribute is uneditable. While you can toggle it to editable in the FileTypes preferences panel, this for some reason still won’t let you edit the attribute in the Tracker.
However, you can still edit the attribute manually, either by using the command line tools rmattr and addattr, or by using a simple GUI tool like the excellent Toothpick add-on.
Remember, if you use BeatWare Mail-It, you’ll need to re-build the cache for that folder by Ctrl-clicking the folder in which the message lives.