To call Project Manager in SynWrite, use one of the following:
Project Manager allows to group files into project structure/tree, which then can be saved to disk in a single file (only listing of files/folders is saved, not files themselves). Project files have "synw-proj" extension.
The following toolbar buttons are present in Project Manager:
Projects can be made portable in such a way: put all data files into subfolders of a single folder; and save SynWrite project file into the same folder. Then this data folder is "portable" - you can move it and reopen SynWrite project file with no file paths correction.
The following kinds of tree nodes' drag&drop are possible in the project tree:
You can drag&drop files and folders from Windows Explorer into the project tree. This will add items to the project (considering current tree node selection). When you drop a folder, additional "Add folder to project" dialog apears.
There is "Preview current project file" panel, just press Space while in Project Manager to show/hide this panel. It shows selected project file contents in a temporary read-only editor. You can dock panel to the edge of main SynWrite window. Use button "Open in editor" on this panel to open previewed file for editing.