TYPO3 Core

In CMS 7.6.10 with activated showRefreshLoginPopup (as needed for some auth services), after sessionTimeout the TYPO3 backend is loaded into the login popup window on using the provided re-login form.
In such case two browser windows are open, where the earlier login popup window fails on loading the backend-framesets and the parent backend window fails on CSRF protection token.
The login popup window should activate the parent window and closes oneself, like in the old days.

How to reproduce:
Ensure, your browser allows opening of popup windows.
Set TYPO3_CONF_VARS for BE:

'debug' => false,
'sessionTimeout' => '60',
'showRefreshLoginPopup' => '1',

Login into backend as usual, and wait for a minute. A login popup should appear where you re-login.