diff --git a/PROMS/Volian.Controls.Library/StepTabRibbon.cs b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
index 0dee3df9..638c5112 100644
--- a/PROMS/Volian.Controls.Library/StepTabRibbon.cs
+++ b/PROMS/Volian.Controls.Library/StepTabRibbon.cs
@@ -2588,7 +2588,8 @@ namespace Volian.Controls.Library
 			{
 				// Selected table cell is not in edit mode. Go into edit mode and position according
 				// to the pass in selOpt.
-				if (MyFlexGrid != null && MyFlexGrid.Editor == null)
+				// B2021-090 don't try to get the font size on an RO table
+				if (MyFlexGrid != null && MyFlexGrid.Editor == null && !MyFlexGrid.IsRoTable)
 				{
 					float fntSz = 0;
 					C1.Win.C1FlexGrid.CellRange cr = MyFlexGrid.Selection; // get the selected grid cell range
@@ -4291,6 +4292,16 @@ namespace Volian.Controls.Library
 			// C2021-005 - setup the font size dropdowns for the table ribbon and context menu
 			//             A list of font sizes is set in the base format file and can be overidden in a plant's format file
 			string tfntszs = MyItemInfo.ActiveFormat.PlantFormat.FormatData.FontSizes.TableFontSizes;
+			// B2021-090 If the current formats were not updated then there will be no list of table font sizes
+			//          so in this case we want to disable the font size dropdown list in the table ribbon and in the context menu
+			if (tfntszs == null)
+			{
+				btnCMChgFontSize.Enabled = false;
+				rbTblFont.Enabled = false;
+				rbTblFntSz.Enabled = false;
+				cmFontSizeList.Enabled = false;
+				return;
+			}
 			rbTblFntSz.Items.Clear();
 			cmFontSizeList.Items.Clear();
 			rbTblFntSz.Items.AddRange(tfntszs.Replace(" ", "").Split(",".ToCharArray())); // dropdown on table ribbon
@@ -4325,7 +4336,9 @@ namespace Volian.Controls.Library
 			btnTblDgnPaste.Enabled = ((VlnFlexGrid.MyCopyInfo.MyCopiedFlexGrid != null) && enableContent);
 			btnTblDgnSplitCells.Enabled = enableContent;
 			btnCmGridSplitCell.Enabled = enableContent;
-			
+			//B2021-090 don't enable the font size selection on RO tables - was crashing trying to read font sizes on an RO table
+			//          enableContent is set to false (above) when on an RO table
+			rbTblFont.Enabled = enableContent; 
 		}
 		public void SetRibbonForGridCellIndent()
 		{