--- src/math-equation.vala	2013-06-17 15:39:06.506824951 -0500
+++ src/math-equation_basefix.vala	2013-06-17 15:38:49.810824504 -0500
@@ -236,6 +236,8 @@
 
             var start = ans_start.get_offset ();
             @delete (ref ans_start, ref ans_end);
+            get_iter_at_mark(out ans_start, ans_start_mark);
+            get_iter_at_mark(out ans_end, ans_end_mark);
             insert_with_tags (ans_end, ans_text, -1, ans_tag);
 
             /* There seems to be a bug in the marks as they alternate being the correct and incorrect ways.  Reset them */
