pLisp now has a File Browser too, for those who are not so enamoured with image-based development:
It's pretty much bare-bones functional; you can open, edit and save files (it's multi-tabbed, so simultaneous handling of multiple files is supported). The programming-specific features are the bells and whistles that are carried over from the Workspace: evaluating expressions, syntax highlighting, autocomplete, parens-matching, and context-sensitive help both via the F1 key and displaying function signatures in the status bar.
