diff --git a/include/msksheet.cpp b/include/msksheet.cpp
index 931c09ade..4556de43e 100755
--- a/include/msksheet.cpp
+++ b/include/msksheet.cpp
@@ -2700,7 +2700,9 @@ void TSheet_field::highlight() const
       if (s->notify(s->_cur_rec, K_TAB))
       {
         s->set_focus_cell(s->_cur_row, s->_cur_col);
-        s->str2mask(selected());
+				const int curr = selected();
+				if (curr >= 0)
+          s->str2mask(curr);
       }  
     }  
   }