Dear list -
Thanks for all your help.
Finally, I can start Iceweasel from the command line [sort of]:
iceweasel -no-remote localhost/choice.php width $1280 height $800
The above works.
But ... in a store.desktop multiple windows are opened.
Exec=iceweasel -no-remote localhost/choice.php width $1280 height $800
FYI Iceweasel is NOT running when I issue the command or click on the icon.
The suggestions on migrating icedove to Thunderbird look excellent.
I'm reasonably good at three things at one time, but six is a little
much. As soon as I can climb out of the hole I am in, I'll do the
migration and give a detailed answer.