Enter Key Breaks Children in Custom Toggleable Blocks

[FatefulNur]

Describe the bug
When pressing Enter inside a custom toggleable block, the children are broken unexpectedly.

• If the cursor is on the toggle title, all children should be preserved, but they are not.
• If the cursor is inside the children, pressing Enter should move the cursor to the next child (if it exists) or create a new default block.

To Reproduce

1. Open the example: https://www.blocknotejs.org/examples/custom-schema/toggleable-blocks
2. Place the cursor in the toggle title and press Enter.
3. Observe that the children are broken.

Misc

• Node version: 22.13.0
• Package manager: npm
• Browser: Firefox
• I'm a sponsor and would appreciate if you could look into this sooner than later 💖

Screencast.from.2025-09-13.21-28-46.webm