Index: trunk/src/libcschem/cnc_text.c
===================================================================
--- trunk/src/libcschem/cnc_text.c	(revision 1818)
+++ trunk/src/libcschem/cnc_text.c	(revision 1819)
@@ -309,10 +309,15 @@
 	int undoable)
 {
 	undo_text_modify_t utmp, *u = &utmp;
-	char **text = (char **)text_;
+	char **text = (char **)text_, *tmp;
 
 	if (undoable) u = uundo_append(&sheet->undo, &undo_text_modify, sizeof(undo_text_modify_t));
 
+	if (text != NULL) {
+		tmp = rnd_strdup(*text);
+		text = &tmp;
+	}
+
 	u->texto = texto;
 	u->spec1.x = (x1 == NULL) ? texto->spec1.x : *x1;
 	u->spec1.y = (y1 == NULL) ? texto->spec1.y : *y1;
Index: trunk/src/libcschem/cnc_text.h
===================================================================
--- trunk/src/libcschem/cnc_text.h	(revision 1818)
+++ trunk/src/libcschem/cnc_text.h	(revision 1819)
@@ -75,6 +75,7 @@
 csch_text_t *csch_text_get(csch_sheet_t *sheet, csch_cgrp_t *grp, csch_oid_t oid);
 void csch_text_update(csch_sheet_t *sheet, csch_text_t *text, int do_xform);
 
+/* if text is not NULL, it's strdup'd */
 void csch_text_modify(csch_sheet_t *sheet, csch_text_t *texto,
 	csch_coord_t *x1, csch_coord_t *y1, csch_coord_t *x2, csch_coord_t *y2,
 	double *rot, csch_halign_t *halign, const char **text, int *has_bbox, int *dyntext,