Why do some Magento extensions "grab" the initial system->configuration page away from the General tab?

So, in the class

app/code/core/Mage/Adminhtml/Block/System/Config/Tabs.php

There's the following loop in the initTabs method.

foreach ($sections as $section) {            
    Mage::dispatchEvent('adminhtml_block_system_config_init_tab_sections_before', array('section' => $section));
    $hasChildren = $configFields->hasChildren($section, $websiteCode, $storeCode);

    //$code = $section->getPath();
    $code = $section->getName();

    $sectionAllowed = $this->checkSectionPermissions($code);
    if ((empty($current) && $sectionAllowed)) {

        $current = $code;
        $this->getRequest()->setParam('section', $current);
    }
    
    //...
}

If the $current variable is empty/null, it will be set the first time through the loop. This variable is set at the start of the method

$current = $this->getRequest()->getParam('section');

Which means on the default configuration page, since there's no section parameter, $current is empty/null.

So, now we need to figure out why our section nodes are ordered in a particular way. In the same initTabs method, the sections nodes are loaded with the following

$sections = $configFields->getSections($current);

Since $current is null, this means all system.xml section nodes are returned. Later in the function, these nodes get cast as an array, and then sorted

$sections = (array)$sections;
usort($sections, array($this, '_sort'));

The sort method looks like this

protected function _sort($a, $b)
{
    return (int)$a->sort_order < (int)$b->sort_order ? -1 : ((int)$a->sort_order > (int)$b->sort_order ? 1 : 0);
}

So, if a module section has a sort order that's less than 10

<sections>
    <!-- ... -->
    <general translate="label" module="core">
        <label>General</label>
        <tab>general</tab>
        <frontend_type>text</frontend_type>
        <sort_order>10</sort_order>
    <!-- ... -->

it will be sorted sooner than the general section, which means it will come first in the $sections loop, and be chose and the default section.

This includes section nodes that have no sort_order. Module authors can fix this "I was just installed and I get to be displayed first" behavior by explicitly including a sort_order in their system configuration section, and ensuring it's greater than 10.

astorm/gist:5479072