I have been building a module and making numerous changes without any problems until just now:
I removed a configuration variable from my extension's system.xml file but the field is still in the config. I disabled all caching, flushed all caches (both through magento admin and by manually deleting everything in the directories) but it STILL won't go away.
As a test, I added it back to the system.xml file using the same node name but changing the label and it picked up the change. I was also able to hide it by setting <show_in_...> to 0. However, after it went away, I removed it from the system.xml file and it showed up again in the admin. I have to imagine this is a caching issue but I can't figure out what to flush to make it go away.
Any thoughts?
Two things to check. When you save a configuration value, magento (currently) persists it to the core_config_data table. Even if you remove the configuration field from your system.xml config. that path/value pair will still be stores in this database. Do a
SELECT * FROM core_config_data WHERE path = '/foo/baz/bar'
To see if there's still a values in there. If it is, calls to Mage::getStoreConfig will still return a value, again regardless of what's in system.xml
Secondly, Magento allows you to stores a default value for each configuration path in config.xml. Look under the
<default>
<foo>
<baz>
<bar>1</bar>
</baz>
</foo>
</default>
node for a nested tree path that matches your configuration path. If this node is present then this value will be returned for requests to Mage::getStoreConfig.