use the same default value as one in the form.

bt5/erp5_knowledge_pad/SkinTemplateItem/portal_skins/erp5_knowledge_pad/Base_viewKnowledgePadFieldLibrary/my_gadget_listbox.xml

@@ -165,7 +165,7 @@
       <dictionary>
         <item>
             <key> <string>_text</string> </key>
-            <value> <string>python: int(context.restrictedTraverse(context.REQUEST.get(\'box_relative_url\', \'\')).KnowledgeBox_getDefaultPreferencesDict().get(\'listbox_selection_list_lines\', None) or 5)</string> </value>
+            <value> <string>python: int(context.restrictedTraverse(context.REQUEST.get(\'box_relative_url\', \'\')).KnowledgeBox_getDefaultPreferencesDict().get(\'listbox_selection_list_lines\', None) or 10)</string> </value>
         </item>
       </dictionary>
     </pickle>

bt5/erp5_knowledge_pad/bt/revision

-728
\ No newline at end of file
+729
\ No newline at end of file