diff --git a/Src/LexText/LexTextControls/MSAGroupBox.cs b/Src/LexText/LexTextControls/MSAGroupBox.cs
index 49445e0570..b5a90a24e0 100644
--- a/Src/LexText/LexTextControls/MSAGroupBox.cs
+++ b/Src/LexText/LexTextControls/MSAGroupBox.cs
@@ -743,8 +743,8 @@ private IEnumerable<IMoInflAffixSlot> GetSlots()
 			if (m_morphType == null)
 			{
 				// Not called by InsertEntryDlg; need to figure out the morphtype(s)
-				var lex = m_propertyTable.GetValue<ILexEntry>("ActiveClerkSelectedObject");
-				if (lex != null)
+				var obj = m_propertyTable.GetValue<ICmObject>("ActiveClerkSelectedObject");
+				if (obj is ILexEntry lex)
 				{
 					return DomainObjectServices.GetSlots(m_cache, lex, m_selectedMainPOS);
 				}