cannot add list of valid characters

[Michael Galant]

Dear colleagues,

When a student of mine adds in the list of valid characters, one by one, for a particular writing system [using the Writing System Properties dialog box, Characters tab, Valid Characters button], the valid characters seem to be added just fine, and he clicks ok, which takes him back to the Writing Systems Propertes dialog box.  However, if he then clicks again on the Valid Characters button, the valid characters list is entirely empty.

Any thoughts on how to remedy this?

Thanks,
Mike