React Scheduler > Scheduler automatically expands the children of the dragged

Hello,

This is our data values for resource and event.

const resource = {
    "id": "phase--1081526",
    "minHeight": 55,
    "expanded": false,
    "children": [
        {
            "id": "milestone--1365016",
            "minHeight": 55,
            "expanded": false,
            "children": []
        },
        {
            "id": "milestone--1365015",
            "minHeight": 55,
            "expanded": false,
            "children": []
        },
        {
            "id": "phase--1363775",
            "minHeight": 55,
            "expanded": false,
            "children": []
        }
    ]
}

const events = [{
    "id": "phase--1081526",
    "start": "2025-08-30T00:00:00",
    "end": "2025-11-10T23:59:59.999",
    "resource": "phase--1081526",
    "height": 23,
    "clickDisabled": false,
    "text": ""
}]

<Scheduler resources={resources} events={events} />

This is the initial state of the app, where nothing is expanded.

When I start to move the “Phase 1” (id = “phase--1081526”) event bar, its children automatically appears, as if the group is expanded. However, we are sure that there is no code that updates the collapse state (we store it in a useState) while moving the item.

Observation:

• When console logging `resources` array, I notice the `expanded` flag becomes true for the moved resource (Phase 1, or id = “phase--1081526”) temporarily, and switches back to false - the original value.

• This issue also happens when I hard-code `expanded` to false always for all the resources.

• Other resources at the same level don’t experience this - only the one being moved.

Can you provide guidance? Thank you!