diff --git a/script/MultiRegion.py b/script/MultiRegion.py
index ed93d441..e6a5eb27 100644
--- a/script/MultiRegion.py
+++ b/script/MultiRegion.py
@@ -44,6 +44,7 @@ def check_region(region):
     """
     check region dictionary items and apply defaults where necessary
     """
+    global ExitSlit
     region['fixed'] = 'efix' in region
     if region['fixed']:
         region['elo'] = region['efix']