Fifth icon from the left on Front Panel is FvwmScript applet. It is calling
f_CheckMail
FVWM function every minute. If clicked, function is called immediately.
By default f_CheckMail
is an empty function. Up to user is to redefine it in his
$FVWM_USERDIR/NsCDE-Functions.local
to suit the needs for mail checking. To be
clear, by default, it is not functional as an applet. Above this applet, there
is an empty space for subpanel launcher which can be activated with middle
click, and it will present Thunderbird entry if thunderbird is installed. User
can use Install Icon action to change or add entries on this menu. For
example, to call urxvt -e mutt or something like that.
Key F1 will bring this help text in browser. If Sun type keyboard is in use, Help key above Check Mail Applet has the same function as F1 on PC.