I tried to set 'vi' as the external editor via:
Pref. Option tabs.
Selected "Use an external editor"
Tried type in vi in the entry box and left open so
system will try to use the "EDITOR" and "VISUAL"
env variable.
Then select Pref. Save options.

Then trie to user it by select Edit, Edit Code
Nothing happen, no xterm was launch.

When turn-off "Use an external editor" option.
System was able to launch a screen to edit code.

Anyone has an idea what's wrong??
Thanks in advance for any assistance.