How to hide header in SugarCRM community edition

In custom/include/MVC/View/views/view.detail.php add the following file:

<?php

/*
 * Your installation or use of this SugarCRM file is subject to the applicable
 * terms available at
 * http://support.sugarcrm.com/06_Customer_Center/10_Master_Subscription_Agreements/.
 * If you do not agree to all of the applicable terms or do not have the
 * authority to bind the entity as an authorized representative, then do not
 * install or use this SugarCRM file.
 *
 * Copyright (C) SugarCRM Inc. All rights reserved.
 */

require_once('include/MVC/View/views/view.detail.php');

class CustomViewDetail extends ViewDetail {

    /**
     * @see SugarView::display()
     */
    public function displayHeader() {
        parent::displayHeader();
        unset($groupTabs['All']);
        $ss->assign("groupTabs",$groupTabs);
    }

}

Override the editview in the same way. In some modules, you'll have to override detailview and editview in that module (i.e. copy modules/<module>/views/view.detail.php to custom/modules/<module>/views/view.detail.php and override the displayHeader class).

In custom/include/MVC/View/views/view.detail.php add the following file:

<?php

/*
 * Your installation or use of this SugarCRM file is subject to the applicable
 * terms available at
 * http://support.sugarcrm.com/06_Customer_Center/10_Master_Subscription_Agreements/.
 * If you do not agree to all of the applicable terms or do not have the
 * authority to bind the entity as an authorized representative, then do not
 * install or use this SugarCRM file.
 *
 * Copyright (C) SugarCRM Inc. All rights reserved.
 */

require_once('include/MVC/View/views/view.detail.php');

class CustomViewDetail extends ViewDetail {

    /**
     * @see SugarView::display()
     */
    public function displayHeader() {
        parent::displayHeader();
        unset($groupTabs['All']);
        $ss->assign("groupTabs",$groupTabs);
    }

}

Override the editview in the same way. In some modules, you'll have to override detailview and editview in that module (i.e. copy modules/<module>/views/view.detail.php to custom/modules/<module>/views/view.detail.php and override the displayHeader class).

As per your suggestion i added following code in this file (custom/modules/Leads/views)

view.detail.php 

require_once('include/MVC/View/views/view.detail.php');

class LeadsViewDetail extends ViewDetail
{

// function display()
// {
// global $sugar_config;

// If the convert lead action has been disabled for already converted leads, disable the action link.
// $disableConvert = ($this->bean->status == 'Converted' && !empty($sugar_config['disable_convert_lead'])) ? TRUE : FALSE;
// $this->ss->assign("DISABLE_CONVERT_ACTION", $disableConvert);
// parent::display();
// }

public function displayHeader() {
parent::displayHeader();
unset($groupTabs['All']);
$ss->assign("groupTabs",$groupTabs);
}

}

but its showing pop up error  that "There was an error processing your request, please try again at a later time."  what's wrong with that .

For anyone else coming to this thread, the correct answer, in addition to the changes in the blogpost is to edit SugarView and remove:

$ss->assign('USE_GROUP_TABS', $usingGroupTabs);

And replace it with:

$ss->assign('USE_GROUP_TABS', false);