TYPO3 Core

I created a new tab for the link handler with PageTSconfig (in combination with https://github.com/cobwebch/linkhandler).

1. I have an input field with an already assigned value (doesn't matter if it is a page id or a record link).
2. I click the wizard icon to open the link popup
3. Then I select my custom tab which lists ~20 of my 100+ records
4. I select one of these first 20 records
5. The field in the backend form gets updated
6. Saving the record and displaying it again shows the new selected value

To this point everything works as expected. Repeat steps 1-3 then follow these next step:

1. Search for a record or simply expand the list to select a record after the first 20 items
2. The input field of the backend form correctly displays the new value
3. Saving the form and displaying it again shows the old one

The problems seems to be that in this case (selecting a record other than the first displayed ones) doesn't populate the hidden field of the input. Therefore the old value gets saved.

This behavior can also be seen if you clear the input value with the (x). If it is a required field it will be highlighted. If you now select a value other than the first 20 records the field will be populated but stays highlighted as required. Saving of the form isn't possible at all now.

I've tested this on TYPO3 7.6.4 and 7.6.5