We noticed that NetXMS has been using the following path as the state directory for cca. 4-5 last minor versions:
org.netxms.nxmc.Startup - State directory: /var/lib/tomcat*/null/state
What's with the "/null/"?
Since this path doesn't exist by default, session settings customizations don't persist until the directory structure is manually created and rw permissions are configured for the tomcat user.
This should be fixed in the current version