bug: applied cuts are lost on every event switch — Cut state is never persisted or re-applied after buildEventDataFromJSON()

[deveshbervar]

Summary

Applied cuts (e.g. η < 0.5 on Tracks) are silently lost on every event
switch. The new event renders all objects visible, ignoring active filters.
The same bug affects Save/Load State — cut values are never serialized.

Root Cause

buildEventDataFromJSON() destroys and recreates all 3D objects on every
event switch:

this.graphicsLibrary.clearEventData();  // all objects destroyed
this.configuration.eventDataLoader.buildEventData(...);  // recreated, all visible=true

No code path re-applies active cuts after rebuild. The Cut objects
(storing minValue, maxValue) live only in Angular component local state
— never stored by any manager, never queried after buildEventData().

StateManager.getStateAsJSON() serializes only camera position and clipping
angles — zero cut data. Confirmed: searching the entire codebase for
storedCuts, activeCuts, cutValues returns no results.

Reproduction

1. ATLAS demo → Tracks_ → Cut Options → set η max to 0.5
2. Observe tracks reduce to central region only
3. Switch to next event
4. All tracks reappear — cut silently lost

Live Screenshots

BEFORE (η < 0.5 applied, tracks filtered):

AFTER (next event loaded, all tracks back, cut ignored):

Impact

Every physicist browsing events with active filters must manually
re-apply cuts after every event switch. Affects ATLAS, LHCb, FCC,
Belle II, TrackML — all use the same code path.

Proposed Fix

1. After buildEventData() completes, re-apply active cuts by calling
   collectionFilter() for each collection with active cuts
2. Add toJSON()/fromJSON() to the Cut class and include cut state
   in StateManager.getStateAsJSON()

Files

• cut.model.ts — Cut class (no serialization)
• scene-manager.ts:290 — collectionFilter()
• event-display.ts:168 — buildEventDataFromJSON()
• state-manager.ts:82 — getStateAsJSON()

[deveshbervar]

I have identified the fix approach and will follow up
with a PR once I confirm the cleanest integration point
between the Angular cut state and buildEventDataFromJSON().
Self-assigning to track.

[EdwardMoyse]

Thanks for looking into this - I think I have encountered this bug, but forgot to open a ticket!

[deveshbervar]

Great to hear it's on your radar! I'll start on the fix this week.