diff --git a/Makefile b/Makefile
index 5e79240bcc3..d575c9b28c8 100644
--- a/Makefile
+++ b/Makefile
@@ -38,8 +38,8 @@ docs-develop: ## Fast doc generation and more warnings (for development)
 setup-venv:
 	if [ ! -f $(VENV)/bin/activate ]; then bash scripts/common_startup.sh --dev-wheels; fi
 
-diff-format:  ## Format Python code changes
-	$(IN_VENV) darker -r $(TARGET_BRANCH)
+diff-format:  ## Format Python code changes since last commit
+	$(IN_VENV) darker .
 
 format:  ## Format Python code base
 	$(IN_VENV) isort .
diff --git a/pyproject.toml b/pyproject.toml
index 5c897f85dbd..68ee31fbe77 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,6 +9,9 @@ extend-exclude = '''
 '''
 force-exclude = 'lib/galaxy/util/jstree.py'
 
+[tool.darker]
+isort = true
+
 [tool.poetry]
 name = "galaxy"
 version = "22.01.dev0"