diff --git a/PROMS/Volian.Controls.Library/StepTabRibbon.cs b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
index 36e5068c..668f7d6d 100644
--- a/PROMS/Volian.Controls.Library/StepTabRibbon.cs
+++ b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
@@ -1377,7 +1377,8 @@ namespace Volian.Controls.Library
 		{
 			if (MyFlexGrid != null )
 			{
-				btnTblDgnMergeCells.Enabled = btnCmGridMergeCells.Enabled =  !MyFlexGrid.IsRoTable  && !MyFlexGrid.IsInMergeRange();
+				// B2017-128 added check for only one cell selected (should not be alowed to merge just a single cell)
+				btnTblDgnMergeCells.Enabled = btnCmGridMergeCells.Enabled =  !MyFlexGrid.IsRoTable  && !MyFlexGrid.IsInMergeRange() && !MyFlexGrid.Selection.IsSingleCell;
 			}
 		}
 		private void SetButtonMenuEnabledDisabledOnSelection(bool setting)