It is not possible to save a new file in the Editor directly to a project within Project Manager. It will be necessary to save the file as normal and then access it via the 'Directory with files' or the Add | Existing File options in Project Manager.
1. If you would like to access all files in a particular directory via the Project Manager you can do the following:
a. Go to View | Project Manager (If Project Manager is not displayed).
b. Click the 'New Project' button, if you would like to create a new one.
c. Right click the project | Add | Directory with files.
d. Once this is in place, the file can be accessed directly from the Project Manager.
2. If you would like to work with only select files from a directory, then add individual files to the project using
Add | Existing file.