diff --git a/dvc/repo/index.py b/dvc/repo/index.py
index 833c4496ad..fe66b65b76 100644
--- a/dvc/repo/index.py
+++ b/dvc/repo/index.py
@@ -413,7 +413,7 @@ def plot_keys(self) -> Dict[str, Set["DataIndexKey"]]:
             by_workspace[workspace].add(key)
 
         for path in self._plot_sources:
-            key = self.repo.fs.path.relparts(path, self.repo.root_dir)
+            key = self.repo.fs.path.parts(path)
             by_workspace["repo"].add(key)
 
         return dict(by_workspace)