diff -r 9a3e4f9cc8f5 -r f37b5995a48c src/pyams_content/workflow/__init__.py
--- a/src/pyams_content/workflow/__init__.py	Fri Jan 26 16:43:14 2018 +0100
+++ b/src/pyams_content/workflow/__init__.py	Fri Jan 26 16:43:52 2018 +0100
@@ -567,7 +567,7 @@
                     menu_css_class='fa fa-fw fa-trash',
                     view_name='wf-delete.html',
                     history_label=_("Version deleted"),
-                    order=18)
+                    order=99)
 
 wf_transitions = [init,
                   draft_to_proposed,
@@ -612,10 +612,14 @@
             request = check_request()
         translate = request.localizer.translate
         state = IWorkflowState(content)
-        state_label = translate(STATES_HEADERS[state.state])
-        if format:
-            state_label = translate(_('{state} {date}')).format(state=state_label,
-                                                                date=format_datetime(state.state_date))
+        header = STATES_HEADERS.get(state.state)
+        if header is not None:
+            state_label = translate(header)
+            if format:
+                state_label = translate(_('{state} {date}')).format(state=state_label,
+                                                                    date=format_datetime(state.state_date))
+        else:
+            state_label = translate(_("Unknown state"))
         return state_label
 
 
@@ -630,10 +634,14 @@
         translate = request.localizer.translate
         state = IWorkflowState(content)
         if len(state.history) <= 2:
-            if state.version_id == 1:
-                state_label = translate(STATES_HEADERS[state.state])
+            header = STATES_HEADERS.get(state.state)
+            if header is not None:
+                if state.version_id == 1:
+                    state_label = translate(header)
+                else:
+                    state_label = translate(_("new version created"))
             else:
-                state_label = translate(_("new version created"))
+                state_label = translate(_("Unknown state"))
         else:
             state_label = translate(_('publication refused'))
         if format: