diff --git a/eeschema/libeditframe.cpp b/eeschema/libeditframe.cpp
index f4eb10a86c..de1c3e8243 100644
--- a/eeschema/libeditframe.cpp
+++ b/eeschema/libeditframe.cpp
@@ -520,7 +520,8 @@ void LIB_EDIT_FRAME::OnUpdatePartModified( wxUpdateUIEvent& aEvent )
     const wxString& libName = libId.GetLibNickname();
 
     aEvent.Enable( !partName.IsEmpty() && !libName.IsEmpty()
-            && m_libMgr->IsPartModified( partName, libName ) );
+            && m_libMgr->IsPartModified( partName, libName )
+            && ( aEvent.GetId() == ID_LIBEDIT_REVERT_PART || !m_libMgr->IsLibraryReadOnly( libName ) ) );
 }