diff --git a/PROMS/Volian.Controls.Library/StepTabRibbon.cs b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
index e2f73f45..786d57c3 100644
--- a/PROMS/Volian.Controls.Library/StepTabRibbon.cs
+++ b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
@@ -480,6 +480,9 @@ namespace Volian.Controls.Library
 				btnCMInsSubStps.SubItems.Clear();
 				btnCMInsRNO.SubItems.Clear();
 			}
+
+			btnInsRNO.Enabled = btnCMInsRNO.Enabled = btnInsRNO.Enabled && (MyItemInfo.RNOs==null || MyItemInfo.RNOs.Count==0);   // don't insert an RNO if has an RNO
+
 			// if (rno is enabled, set the tag:
 			if (btnInsRNO.Enabled)
 				btnInsRNO.Tag = string.Format("{0} {1}", (int)E_FromTypes.RNOs, MyStepItem.MyItemInfo.ActiveFormat.PlantFormat.FormatData.GetIndexFromType("RNOType"));