diff --git a/PROMS/Volian.Controls.Library/DisplayTags.cs b/PROMS/Volian.Controls.Library/DisplayTags.cs
index 1fdb3f89..b984e05a 100644
--- a/PROMS/Volian.Controls.Library/DisplayTags.cs
+++ b/PROMS/Volian.Controls.Library/DisplayTags.cs
@@ -147,7 +147,8 @@ namespace Volian.Controls.Library
 
 		public void ToggleContActSummary() // for use with shortcut keystroke <Shift><F7>
 		{
-			cbCAS.Checked = !cbCAS.Checked;
+			if (cbCAS.Enabled)
+				cbCAS.Checked = !cbCAS.Checked;
 		}
 		public void TogglePlaceKeeper() // for use with shortcut keystroke <Ctrl><F7>
 		{