1. The /imports command is missing.
2. The /classes command in JShell is named /types. The NetBeans JShell plugin should use the same names as the command0line jshell tool.
3. If there are other JShell command-line-tool commands that will not be implemented in the NetBeans JShell plug-in, these should be listed in the help documentation somewhere, perhaps with a brief mention of why. Some will be obvious--for example, there's no need to configure a text editor with "/set editor".
With jet-main#d965ddd6800a, I've integrated (almost) the original tools code. The /set command is deliberately missing as changing the prompt would break the console parsing.