fix #471 - ENTER key doesn't work on non D source if the "alwaysAdvancedFeatures" editor option is not activated

src/u_synmemo.pas

@@ -3538,6 +3538,7 @@ begin
           decCallTipsLvl;
     end;
     VK_RETURN:
+    if isDSource then
     begin
       fCanDscan:=true;
       line := LineText;