diff -r 0d462137f10d -r 77ad84e8b837 src/pyams_form/interfaces/templates/inner-form.pt
--- a/src/pyams_form/interfaces/templates/inner-form.pt	Fri Jun 15 18:17:32 2018 +0200
+++ b/src/pyams_form/interfaces/templates/inner-form.pt	Wed Jun 20 18:14:23 2018 +0200
@@ -53,7 +53,8 @@
 												data-ams-checker-readonly 'readonly' if group.checkbox_widget.mode == 'display' else None;
 												data-ams-checker-mode 'disable' if group.checkbox_mode == 'disable' else None;
 												data-ams-checker-marker '{0}-empty-marker'.format(group.checkbox_widget.name);
-												data-ams-checker-state group.checker_state;">
+												data-ams-checker-state group.checker_state;
+												data-ams-data extension:object_data(group);">
 							<label tal:content="legend">Legend</label>
 						</legend>
 					</tal:if>