Puntuado con 5 de 5 estrellas
Thanks for this add-on. I immediately searched for "compact headers" after the update to TB 78 and was relieved to find a working one.
@Nibinaear: Settings are available via the context menu of the angle bracket which shows the normal/compact mode state; so just click with the right mouse button on it.
@Firefox user f5aa39: I use Message Header Toolbar Customize (https://addons.thunderbird.net/de/thunderbird/addon/msghdr-toolbar-customize/) for this additionally.
@Eric March: You can give 5 stars now since it fully works in TB 78 and you can set one line or two lines.