Index: trunk/scconfig/Rev.h
===================================================================
--- trunk/scconfig/Rev.h	(revision 7410)
+++ trunk/scconfig/Rev.h	(revision 7411)
@@ -1 +1 @@
-static const int myrev = 7398;
+static const int myrev = 7411;
Index: trunk/scconfig/Rev.tab
===================================================================
--- trunk/scconfig/Rev.tab	(revision 7410)
+++ trunk/scconfig/Rev.tab	(revision 7411)
@@ -1,4 +1,4 @@
-7398	configure	new plugin for non-graphical tEDAx sheets
+7411	configure	new plugin for non-graphical tEDAx sheets
 7370	configure	cleanup: get rid of local "inline" defs
 7322	configure	enable io_altium by default
 7257	configure	plugin config for io_altium
Index: trunk/src/libcschem/Makefile.in
===================================================================
--- trunk/src/libcschem/Makefile.in	(revision 7410)
+++ trunk/src/libcschem/Makefile.in	(revision 7411)
@@ -32,6 +32,7 @@
  integrity.o
  intersect.o
  libcschem.o
+ non_graphical.o
  oidpath.o
  op_common.o
  operation.o
Index: trunk/src/libcschem/non_graphical.c
===================================================================
--- trunk/src/libcschem/non_graphical.c	(nonexistent)
+++ trunk/src/libcschem/non_graphical.c	(revision 7411)
@@ -0,0 +1,45 @@
+/*
+ *                            COPYRIGHT
+ *
+ *  cschem - modular/flexible schematics editor - sch-rnd (executable)
+ *  Copyright (C) 2023 Tibor 'Igor2' Palinkas
+ *
+ *  (Supported by NLnet NGI0 Entrust in 2023)
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.*
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ *  Contact:
+ *    Project page: http://repo.hu/projects/sch-rnd
+ *    contact lead developer: http://www.repo.hu/projects/sch-rnd/contact.html
+ *    mailing list: http://www.repo.hu/projects/sch-rnd/contact.html
+ */
+
+#include "config.h"
+
+#include "concrete.h"
+#include "non_graphical.h"
+
+void csch_non_graphical_impl_pre_unload(csch_non_graphical_impl_t *impl)
+{
+	rnd_design_t *curr;
+	for(curr = gdl_first(&rnd_designs); curr != NULL; curr = gdl_next(&rnd_designs, curr)) {
+		csch_sheet_t *sheet = (csch_sheet_t *)curr;
+		if (sheet->non_graphical && (sheet->non_graphical_impl == impl) && (impl->free_sheet != NULL)) {
+			impl->free_sheet(sheet);
+			sheet->non_graphical_impl = NULL;
+			sheet->non_graphical_data = NULL;
+		}
+	}
+}
Index: trunk/src/libcschem/non_graphical.h
===================================================================
--- trunk/src/libcschem/non_graphical.h	(revision 7410)
+++ trunk/src/libcschem/non_graphical.h	(revision 7411)
@@ -34,3 +34,8 @@
 };
 
 
+/* Iterate over all sheets and call ->free_sheet() if the sheet is handled
+   by impl. This should be called before a plugin that implements
+   non_graphical sheets is unloaded so the callbacks are not left behind */
+void csch_non_graphical_impl_pre_unload(csch_non_graphical_impl_t *impl);
+