Source tab

The Source tab lets you specify where the debugger should look for source files. By default, the debugger looks in your project area in your workspace, but you can specify other source locations.

The Source Lookup Path panel lists the "source containers", which define the source code paths. The search order of the paths is from top to bottom in the list. If you click the Add button, the Add Source window appears and lists these container types:
Absolute File Path
Use any source file path compiled into the binary. The IDE interprets all paths "as is", meaning if you're debugging a source file compiled with a path of /foo on another machine, your host machine must store that file at the same absolute path for the IDE to find it.
Compilation Directory
A local directory used for running the C/C++ compiler. You can specify the directory in the popup selector, which lets you browse the filesystem.
File System Directory
A local directory. This container type is similar to Compilation Directory except you can name any local directory, not just one used by the C/C++ compiler.
Path Mapping
A mapping of paths compiled into the binary to equivalent local paths. For instance, if the compilation path for some source files is /foo but the host location of these files is /tmp/foo, you must define a mapping between these directories so the debugger can find the files.
Program Relative File Path
Use any relative path compiled into the binary. You should use this container type when your host's directory structure matches that of the development system.
One of more workspace projects. You can select these projects from a file selector. For each container of this type, the IDE searches recursively within the project, without considering the relative paths of the source files.
Project - Path Relative to Source Folders
This container type is similar to Project except that the IDE examines the relative paths in the compiled-in source file locations.
All projects in the workspace.
Workspace Folder
One or more workspace folders. You can select these folders from a file selector.

If you need to revert to the original lookup paths, you can click the Restore Default button. There are also buttons for editing the location in directory-specific containers, deleting containers, and moving them up or down in the list to change the directory search order.

When Search for duplicate source files on the path is checked, the IDE continues to search the lookup paths for a source file with the same name even after finding the first file with a matching name.