Version:            (using KDE 4.2.3)
Compiler:          cc
OS:                Linux (i686) release 2.6.28-12-generic
Installed from:    Ubuntu Packages

When creating new massage via menu of  (choosing "New massage" there), the massage editor doesn't start with a general default identity, but with an identity set as default for the folder which was opened for the last time in KMail.

For example, 
-- having two IMAP accounts with two identities for them (the one for the first IMAP as general default identity, the other as default for the second IMAP account) and a bunch of folders filtering mail from different POP3 accounts (with different identities associated with them) 
-- and choosing any mail folder X not associated with the general default identity (i.e. not the first IMAP), 
-- than closing even all Kontact's windows,
still creating a new massage via KMail's system tray notifier/icon ("New massage"), the massage composer won't start with the general default identity (as in KDE 3.5 as far as I remember), but with the identity associated with folder X.

That's evidently a bug, since if there is any sense in setting a general default identity, that's it: to be able to start quickly writing a massage with that general identity -- via system tray icon functionality -- which is very handy when having many identities (otherwise one must choose an identity from the list in the composer or navigate to an appropriate folder and start composing a massage from there).