Mail preference window stays hiden

[BERLY]

Hello,
I cannot change any Mail preference any more.
When I choose Preferences in the Mail menu, nothing happens.

Does anybody know how to repair that?
Probably by trashing a file••¦ but what file?

Thanks
Regards
Christophe

[sdemott]

trash:

~/Library/Preferences/com.apple.mail.plist

Now when you launch mail you should be able to see the prefs window.