Precondition:
Open dashboard, using developer tools replace "Dashboard" link href attribute from relative URL to absolute URL prepending string test:test@ before domain name, for example "zabbix.php?action=dashboard.view&ddreset=1" should be replaced to "http://test:test@your.domain/zabbix.php?action=dashboard.view&ddreset=1".

Steps to reproduce:
1. Click on link with replaced URL.
2. Open any form with tabs, for trunk you can open dashboard.

Result:
Opened page is included as tab content.

Expected:
Opened page is not included as tab content.

Moved from ZBXNEXT-4573