[Users] Flagging non-default accounts during compose?

[Pierre Fortin]

Hi,

Almost sent a message from an account that I don't want "out there"...

Is there a way to change the background of the compose window for all but
the default account to some color (say yellow) as a warning? 

Some other "obvious" method?  

This is not a problem when sending from a folder with Properties set, or
replying/forwarding; but when trying to send a new message from the inbox
or non-preset folder....

Thanks,
Pierre