Why are my new types not recognized?

ttsession reads the types database on start-up, on receipt of a USR1 signal, or when notified by a special ToolTalk message that the types databases have changed. Normally there is no need to manually update a ttsession to reread the types files. However, if you wish to force a running ttsession to reread the types databases, you may do so by sending it the USR2 signal; for example:

kill -USR2 <ttsession pid>