Steps to reproduce:

1. Install clean installation of Ibexa DXP.
2. Create content object with richtext field (e.g. article) or edit existing one.
3. Add a string in the text editor, select the string and use the "Link" option in the toolbar
4. Add an external link and click "Save"
5. Click on the link in the editor and the edit dialog opens
6. Try to edit something - e.g. select "Open in tab" and click save
7. Click again on the link for edition

Result:

Changes are not saved.

Also, after publishing the content and re-editing, the link cannot be edited. There is no way to save any of the link data on re-edit. The only solution is to completely remove the link and start again.

Expected result:

The changes are saved and edition of the link is possible.