treeline
It can be used to edit bookmark files, create mini-databases (e.g., for addresses, tasks, records, CDs, etc.), outline documents, or just collect ideas. It can also be used as a generic editor for XML files.
The data schemas for any node in the data tree can be customized and new types of nodes can be defined. The way data is presented on the screen, exported to HTML, or printed can be defined with HTML-like templates. Plug-ins can be written to load and save data from and to custom file formats or external data sources and extend the functionality of TreeLine.
Latest reviews
Easy key navigation throuch document structure, exports many formats, customizable shortcuts. Best alternative to commercial ActionOutline in Windows, that I found.
Tried it as a Linux replacement for TreePad Lite. It works: imports TreePad files, and exports a single html file (unlike CherryTree), file format is easily recoverable, xml. But: you can't edit in note pane, have to click on editor tab and enter or correct information in small database entry window, keyhole-like view. Tabs clutter interface, no options to remove them. Great functionality, works smoothly (once you figure out in what format you should create your documents). Good, solid program, but Gjots, in its simplicity, is better for my tasks, if only it had better TreePad import (imports hierarchy as single note).