Index: openacs-4/packages/xowiki/tcl/bootstrap-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/bootstrap-procs.tcl,v
diff -u -r1.11 -r1.11.2.1
--- openacs-4/packages/xowiki/tcl/bootstrap-procs.tcl	17 Dec 2018 10:39:11 -0000	1.11
+++ openacs-4/packages/xowiki/tcl/bootstrap-procs.tcl	18 Apr 2019 07:56:43 -0000	1.11.2.1
@@ -8,6 +8,7 @@
 }
 
 ::xo::library require menu-procs
+::xo::library require -package xotcl-core 30-widget-procs
 
 namespace eval ::xowiki {
   # minimal implementation of Bootstrap "navbar"
@@ -433,7 +434,16 @@
         }
       }
     }
-    set children [:children]
+    ad_try {
+      set children [:children]
+    } on error {errorMsg} {
+      html::div -class "alert alert-danger" {
+        html::span -class danger {
+          html::t $errorMsg
+        }
+      }
+      return
+    }
     html::tbody {
       foreach line [:children] {
         html::tr -class [expr {[incr :__rowcount]%2 ? ${:css.tr.odd-class} : ${:css.tr.even-class} }] {