Allow unsetting the current_file in saved notebook state
Allow unsetting the current_file in saved notebook state

johnrizzo1/reinteract,johnrizzo1/reinteract,rschroll/reinteract,rschroll/reinteract,jbaayen/reinteract,alexey4petrov/reinteract,jbaayen/reinteract,alexey4petrov/reinteract,jbaayen/reinteract,rschroll/reinteract,alexey4petrov/reinteract,johnrizzo1/reinteract