Comment 98 for bug 10883

The Shift+click is useful for Send and Reply, but doesn't work for Forward; and
there is no way to change formats using Edit As New.

From comment 11 (Rudolf Krist):

> you can switch: PLAIN TEXT --> HTML
> but not: HTML --> PLAIN TEXT

The available switch (Options|Format|Plain Text Only) still leaves you composing
with the HTML font, it's not a true plain-text editor. (Which incidentally
leaves you open to bug 125928.)

As of 1.6, making the switch hides the Format and Insert menus, along with the
format toolbar being hidden. Other than the font, the only visible difference
is whether the Options menu has a Format submenu (HTML) or not (plain).