system.xml dependencies across groups/fieldsets

Question

The system.xml allows us to make the visibility of individual fields dependent on values from other fields. The goto article is of course from Alan Storm: In Depth Magento System Configuration

It looks something like this (I am borrowing his example code here):

Location: app/code/local/Alanstormdotcom/Helloworld/etc/system.xml
<config>
<tabs>
 <helloconfig translate="label" module="helloworld">
 <label>Hello Config</label>
 <sort_order>99999</sort_order>
 </helloconfig>
</tabs>
<sections>
 <helloworld_options translate="label" module="helloworld">
 <label>Hello World Config Options</label>
 <tab>helloconfig</tab>
 <frontend_type>text</frontend_type>
 <sort_order>1000</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 <groups>
 <notes translate="label">
 <label>Demo Of Config Fields NOTES</label>
 <frontend_type>text</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 <fields>
 <enabled translate="label">
 <label>Enabled</label>
 <frontend_type>select</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 </enabled>
 <hello_note>
 <label>Message</label>
 <frontend_type>text</frontend_type>
 <sort_order>2</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 <depends>
 <enabled>1</enabled>
 </depends>
 </hello_note>
 </fields>
 </notes>
 <messages translate="label">
 <label>Demo Of Config Fields MESSAGES</label>
 <frontend_type>text</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 <fields>
 <hello_message>
 <label>Message</label>
 <frontend_type>text</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 </hello_message>
 <hello_time>
 <label>Time to Say Hello</label>
 <frontend_type>time</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 </hello_time>
 </fields>
 </messages>
 </groups>
 </helloworld_options>
</sections>

Since this seems to only work with fields inside the same group/fieldset (<notes> in this example), I want to know: is there a way to make <hello_message> from the <messages> group dependent on <enabled> from the <notes> group?

Answer 1

After consulting the appropriate core file a cross group/fieldset <depends> looks like this:

<!-- ... -->
<hello_message>
 <label>Message</label>
 <frontend_type>text</frontend_type>
 <sort_order>1</sort_order>
 <show_in_default>1</show_in_default>
 <show_in_website>1</show_in_website>
 <show_in_store>1</show_in_store>
 <depends>
 <enabled>
 <fieldset>notes</fieldset>
 <value>1</value>
 </enabled>
 </depends>
</hello_message>
<!-- ... -->