Jmol version 16.4.1 allows only once to open "JSpecView". (See attached video)
Info from Jmol console:
(C) 2015 Jmol Development
Jmol Version: 16.4.1 2026-05-14 14:21
java.vendor: Java: BellSoft
java.version: Java 25
os: Windows 10 amd64
Access: ALL
memory: 24.9/134.2
processors available: 4
useCommandThread: false
Jmol version 16.3.55 work as expected (see attached video).
Thank you. And, in fact, it was not functional at all. This is fixed for Jmol 16.4.3