There is at least one entry in system-config-printer which uses a '*' instead of the bullet character we use in the rest of the desktop. Its best to just remove all setting of the invisible-char property from the glade file, and just use the gtk default.
Created attachment 137774 [details] patch
The bug is in glade-2, which always writes these out. At one point I had to change it to a '*' character because the entry box wasn't working at all. (It seems to be working now though..)
Fixed in CVS.
Fixed in update: system-config-printer-0.7.35-1.fc6