diff --git a/ReleaseNotes/release_notes.md b/ReleaseNotes/release_notes.md
index 497dcb50..f9bf4f0d 100644
--- a/ReleaseNotes/release_notes.md
+++ b/ReleaseNotes/release_notes.md
@@ -3,8 +3,9 @@
 ## Backward incompatible
     
 ## Bug fixes
-
-
+    
+ 1. fix a typo in `graphs.py` (thanks to Dima Pereima!)
+    
 # v1.13.8.0
 
 ## New features
diff --git a/ostap/histos/graphs.py b/ostap/histos/graphs.py
index 5718e834..af2f1b9c 100755
--- a/ostap/histos/graphs.py
+++ b/ostap/histos/graphs.py
@@ -1817,7 +1817,7 @@ def _color_ ( self ,
     if hasattr ( self , 'SetFillStyle'      ) :
         if   fill is True  : self.SetFillStyle ( 1001 )        
         elif fill is False : self.SetFillStyle (    0 )        
-        elif insinstance ( fill , integer_types ) and 1000 < fill :
+        elif isinstance ( fill , integer_types ) and 1000 < fill :
             self.SetFillStyle ( fill )
             
     if hasattr ( self , 'SetFillColorAlpha' ) and isinstance ( opacity , num_types ) and 0 <= opacity <= 1  :