What should be the name of controllers in magento?

Question

Magento

Here is the code snippet from the etc/config.xml file

<adminhtml>
    <menu>
        <cmindscmsmenu module="cmindscmsmenu">
            <title>CMS Menu</title>
            <sort_order>100</sort_order>
            <action>cmindscmsmenu_admin/adminhtml_cmsmenu</action>			
        </cmindscmsmenu>
    </menu>
</adminhtml>

Here, in fact, the controller itself controllers/CmsMenuController.php

<?php

class Cminds_CmsMenu_Adminhtml_CmsMenuController extends Mage_Adminhtml_Controller_Action
{
  public function indexAction()
  {
            $this->loadLayout();
            $this->_setActiveMenu('cmindscmsmenu');

            $contentBlock = $this->getLayout()->createBlock('cmindscmsmenu/adminhtml_CmsMenu');
          
            $this->_addContent($contentBlock);
            $this->renderLayout();
  }
}

In the browser, when I click on the link
magento.dev/index.php/cmindscmsmenu_admin/adminhtml_cmsmenu/index/key/08c8a4c5094a4609b84df9adb3fc02ac/
I get a 404 error!
But if in config.xml in action replace cmindscmsmenu_admin/adminhtml_CmsMenu, i.e. put capital letters, then everything works! The controller is loading!
Is it possible to name the controller the way I have it named? Or what could be the problem?