TYPO3 Core

Problem:
When using folder selector within a content element in backend to add a path to folder, the selector is adding a parent folder instead of the selected folder.
Steps to reproduce:

1. TCA: add an item for selecting folders. Example code (flexform):

<settings.folders>
   <TCEforms>
       <label>Folders</label>
       <config>
           <type>group</type>
           <internal_type>folder</internal_type>
           <size>10</size>
           <maxitems>10</maxitems>
           <minitems>1</minitems>
       </config>
   </TCEforms>
</settings.folders>

2. Clear all Caches

3. Choose in BE/Pages a matching content element => edit => open folder selector

4. Navigate within the left part and klick to any folder containing subfolders.

5. At the right part klick at the subfolder (having a plus-symbol) or klick at plus-symbol and close the pop-up.

Expected result:
subfolder is selected

Actual result:
parent folder is selected instead