[Bug]: Documents — confirm dialogs in the document editor crash Studio (React error #321) #628

Affected Version

2026.3

Affected capability

Documents

Steps to reproduce

1. Open a document with a relations editable in Studio, e.g. on the public demo "Editable Roundup" (/en/More-Stuff/Developers-Corner/Editable-Roundup).
2. Click "Remove all" below the relations editable, or the trash icon in a row if it has relations.

Actual Behavior

Studio turns into a white page with "Minified React error #321". Console:

Error: Minified React error #321
    at t.useContext (remoteEntry.js)
    at Object.jZ [as useToken] (remoteEntry.js)
    at __federation_expose_app.js   (createStyles)
    at c                            (useDraggableModal)
    at n                            (DraggableModalRender)

Since pimcore/studio-ui-bundle#3931, useStudioModal() wraps every imperative modal with withDraggableModalRender(), also the parent window's modal it uses inside the document editor iframe. The DraggableModalRender component then comes from the iframe's React, but it is rendered by the parent window's React, so its hooks fail. Every confirm dialog opened from the document editor is affected.

Impact: regression since 2026.3.0, every 2026.3 installation is affected. There is no workaround in the UI — relations can't be removed from a document at all, and staying on 2026.2 is not possible with platform 2026.3. Per the code, alert modals from the iframe (useAlertModal, e.g. the relation limit warning) and the confirms of the image, embed and scheduled block editables take the same path.

Fix: pimcore/studio-ui-bundle#4218

Expected Behavior

The confirm dialog opens in the main window and the relation can be removed.