[Orgmode] Remember string prompt won't accept spaces %^{Prompt text}

[Charles Cave]

I have set up Remember with org-mode and found that the prompt
directive doesn't allow spaces in the input.

This is the directive (to capture Internet banking
receipts)  .....

 '(("Receipt"   ?r "** %^{BriefDesc} %U %^g\n%?" "~/GTD/GTD/finances.org")

After I issue the command C-c r  and choose r (for Receipt)
I see the new window for Remember filled in like this:

**  [2008-01-01 Tue 21:02] %^g
%?


And in the minibuffer, a prompt:

BriefDesc:
As soon as I type a space I get a message [No Match].

Why can't I enter a space?   I am running org-mode 5.17a
on GNU Emacs 22.1.1 on Windows XP.


Thanks
Charles