TYPO3 Core

After further investigation, I found, that changing initDocumentTemplate would only fix the linkhandler extension, which relies on the parameters and appends them in URLs.

The problem with the Link Browser popup and creating a folder would still exist. This would need a more complex fix.
One solution would be to add the fieldChangeFunc parameter in the action url of the form for creating a folder / uploading a file.

Another fix would be to send an event to the opener-window instead of using parameters of the opener window to find the form element there.

Yes TYPO3 7.6 is affected as well.

It works correctly in TYPO3 6.2

Just a note: This bug is still present with 7.6.13 and not fixed with #75743

The problem lies in the fact that all the forms in the file tab of the link browser (creating a folder, uploading a file, adding a media asset) have a faulty
redirect value. See here https://github.com/TYPO3/TYPO3.CMS/blob/TYPO3_7-6/typo3/sysext/recordlist/Classes/View/FolderUtilityRenderer.php#L81

After form submission TYPO3 redirects to that URL, and the parameters to figure out which form input to update in the parent window are lost.
They are computed here: https://github.com/TYPO3/TYPO3.CMS/blob/TYPO3_7-6/typo3/sysext/recordlist/Classes/Controller/AbstractLinkBrowserController.php#L593
A possible fix would be to extend FileLinkHandler::getUrlParameters https://github.com/TYPO3/TYPO3.CMS/blob/TYPO3_7-6/typo3/sysext/recordlist/Classes/LinkHandler/FileLinkHandler.php#L313 to return these add-on parameters as well.

Thanks for investigating. Do you have a patch at hand already? If so, please push it to Gerrit and add me as reviewer. Thanks.

Affects also 8.7.1-dev (latest master) AFAICS

Thanks for testing. It must have been fixed with the new link wizard in TYPO3 v8.