diff --git a/tryton/gui/window/view_form/view/form_gtk/url.py b/tryton/gui/window/view_form/view/form_gtk/url.py
index e7615868a3..cd547c7dcc 100644
--- a/tryton/gui/window/view_form/view/form_gtk/url.py
+++ b/tryton/gui/window/view_form/view/form_gtk/url.py
@@ -159,7 +159,8 @@ class HTML(Widget, TranslateMixin):
 
     def _readonly_set(self, value):
         super()._readonly_set(value)
-        self.button.set_sensitive(not value)
+        for button in self.widget.get_children():
+            button.set_sensitive(not value)
 
     def translate_dialog(self, languages):
         languages = {l['name']: l['code'] for l in languages}