User Manager prevents creation of a user name with an embedded dollar ($), but allows a dollar ($) at the end of the user name. 
When the user name has a $ at the end, many of the gnome configuration tools do not work. For instance if I right click on a panel, the "+ Add To Panel" menu item is greyed out. I think this is because gnome cannot find its configuration files. 
In addition latex gets pretty confused, spits out copious error messages, but never the less seems to produce legal output.
This could all be pretty confusing to a new user, it certainly had me scratching my head for a while (thanks sys-admin).


Version-Release number of selected component (if applicable):
FC-10 with all updates as of Feb-22. rpm -q reports
system-config-users-1.2.81-1.fc10.noarch

How reproducible:
100%


Steps to Reproduce:
1. Create a new user account using system-config-users with a username ending in a dollar, for instance bar$
2. Switch to the new account
3. Try to add an item to the main panel, or run System->Preferences->Look and Feel->Appearance
  
Actual results:
As described above


Expected results:
Either $'s should be disallowed at any position in a user name, at least
when created by system-config-users, or gnome and latex should be fixed to accept trailing $'s in user names. I think we can presume that people who are
directly editing passwd know what they are doing.....


Additional info:
I did not check for the effect of any other "special" characters in user names, so it might be worth doing this.