diff --git a/tryton/gui/window/view_form/view/form.py b/tryton/gui/window/view_form/view/form.py
index f41a4c02a9..12bc70aa88 100644
--- a/tryton/gui/window/view_form/view/form.py
+++ b/tryton/gui/window/view_form/view/form.py
@@ -43,6 +43,12 @@ class ViewForm(ParserView):
         viewport.add(scroll)
         if isinstance(self.screen.window, gtk.Dialog):
             width, height = self.widget.size_request()
+            if self.screen.window:
+                parent = self.screen.window.get_transient_for()
+                if parent:
+                    parent_width, parent_height = parent.get_size()
+                    width = min(parent_width - 40, width)
+                    height = min(parent_height - 80, height)
             vbox.set_size_request(width or -1, height or -1)
         vbox.pack_start(viewport, expand=True, fill=True)
 
diff --git a/tryton/wizard/main.py b/tryton/wizard/main.py
index ec9479235b..6cb22a3aec 100644
--- a/tryton/wizard/main.py
+++ b/tryton/wizard/main.py
@@ -103,10 +103,10 @@ class Dialog(object):
         width, height = self.screen.screen_container.size_get()
         parent_width, parent_height = parent.get_size()
         dia_width, dia_height = self.dia.get_size()
-        self.widget_width = max(min(parent_width - 20,
-            max(dia_width, width + 20)), size[0])
-        self.widget_height = max(min(parent_height - 60,
-            height + dia_height + 20), size[1])
+        self.widget_width = min(parent_width - 20,
+            max(dia_width, width + 20, size[0]))
+        self.widget_height = min(parent_height - 60,
+            max(height + dia_height + 20, size[1]))
         self.dia.set_default_size(self.widget_width,
                 self.widget_height)
         self.screen.widget.show()