minimize Thunderbird to tray on clicking the close 'X' instead of closing
Presently I have minimize Thunderbird to tray icon set, this is fine. But I want Thunderbird to minimize to tray icon when I click the 'X' instead of closing out altogether. Since there's no setting for this, is there some kind of secret sauce like an add-on or a manual mod of the registry to enable this?
Many thanks.