Cover the arrangement the Gmail sidebar actually asks for

Shipped

September 5, 2026 at 6:39 AM UTC

Author

Kamo

Commit

07f7fdb

The classification is tested in folderTargets; this is the call the sidebar makes with it. None of Gmail's well-known folders is a root and none is named anything the fixed block recognises, so before the server reported roles every one of them fell through to the member's block — and flattenOrder, which decides what a drag persists, recorded positions for folders that cannot be dragged.