Steps to reproduce:

1. Install clean installation of Ibexa DXP.
2. Edit Landing page content type
3. Add Richtext field to Field definitions
4. Add new section and add any field in this section
5. Save
6. Go to the landing page and edit it in the page builder's "Fields" view

Result:

Width of the fields is reduced, the richtext field's toolbar (similarly for image field type) get cut off on the left and some of the elements are unavailable (screenchot attached).

Expected result:

Fields and toolbars shoould be dispayed correctly.