[BUG] Shift+click bulk selection of linked instance labels has no effect in video datasets

️ Describe the problem

The docs on Linking labels describe two behaviors for labels linked via their instance attribute:

1. Visual linking (on hover) — hovering a label highlights all other labels in the same instance group with a white border.
2. Bulk selection (shift + click) — shift-clicking a label selects/deselects all labels belonging to that same instance in bulk.

Behavior 2 (shift + click bulk selection) does not work for a video dataset.

Shift-clicking a label in the video view selects nothing at all, not the clicked label, and not any other label in the instance group. A normal (non-shift) click correctly selects the single clicked label, but never propagates the selection to other labels of the same instance.

The instance links themselves appear to be set up correctly: after running index_to_instance, every label in the App shows an "Instance id", and I verified for a sample object that the instance id stays constant across frames for the same object.

️ Operating System Platform & Distribution

• Linux
• MacOS
• Windows
• Other (please specify)

System Details

This is observed using the FiftyOne Enterprise Helm deplyoment.

Browser

Chrome (or Chromium-based)

⤵️ Installation type

• Package (pip)
• Source (git)

⌨️ Code to reproduce issue

import fiftyone as fo
import fiftyone.zoo as foz
import fiftyone.utils.labels as foul

dataset = foz.load_zoo_dataset("quickstart-video")
foul.index_to_instance(dataset, "frames.detections", clear_index=True)

session = fo.launch_app(dataset)

Then, in the App:

1. Open a video sample in the video/modal view.
2. Confirm each detection shows an "Instance id" and that the same object keeps the same id across frames.
3. Shift + click a detection.

Expected: all labels belonging to that instance are selected in bulk. Actual: nothing is selected. (A plain click selects only the one clicked label.)

What version of Python?

Python 3.12.13

What version of FiftyOne?

FiftyOne Enterprise 2.25.0

Other info/logs

No response

Willingness to contribute

No, I cannot contribute a bug fix at this time

Upload screenshots

No response