TimeLineRulerMenu: only show drop or non-drop timecode depending

on timebase

app/panel/timebased/timebased.cpp

@@ -34,6 +34,11 @@ rational TimeBasedPanel::GetTime()
   return widget_->GetTime();
 }
 
+rational TimeBasedPanel::timebase()
+{
+  return widget_->timebase();
+}
+
 void TimeBasedPanel::GoToStart()
 {
   widget_->GoToStart();