Timeline: Fix bug in track right click handling.

timeline/src/Sequence.C

@@ -442,6 +442,11 @@ Sequence::handle ( int m )
         }
         default:
         {
+            if ( m != FL_DRAG &&
+                 m != FL_RELEASE &&
+                 Fl::event_x() < drawable_x() )
+                return 0;
+
             Sequence_Widget *r = Sequence_Widget::pushed() ? Sequence_Widget::pushed() : event_widget();
 
 /*             if ( this == Fl::focus() ) */