Flagging conflict with trivial opacity

[adamjohnwright]

Migrated from reactome/PathwayBrowser#21, opened by @EliotRagueneau on 2025-10-09. That repository is archived; the Angular pathway browser now lives here.

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Sometimes, but not always, when navigating between pathways with some entity flagged, trivial entities will not be displayed even when zooming in, while their structure appear correctly.
Flagging is supposed to indeed remove the trivial opacity interactivity, but by leaving them always visible, and not always invisible.

[adamjohnwright]

Two defects found and fixed in a76379e — but I could not reproduce the original report on demand, so leaving this open for confirmation on beta.

1. The zoom handler was often not detached. Flagging detaches the zoom handler so trivial molecules stop fading, looking it up via cy.data('reactome').interactivity. But a single Style is bound to several graphs (diagram, legend, comparison) and that field only holds whichever was bound last. The legend binds inside an async subscribe, so it is a race. Confirmed at runtime — on the legend, style.cy points at the diagram rather than itself. cy.off() matches on function identity, so losing the race means the diagram’s own handler is never removed and keeps re-applying zoom-based opacity. Now looked up per graph via interactivityOf(cy).

2. Visibility rode on an inline style that nothing could restore. The base rule is .trivial { opacity: 0 }, and flagging overrode it with an inline opacity: 1. Inline styles beat stylesheet rules in cytoscape — but with the handler detached, nothing recomputes that value. If it is lost, the base rule takes over and no amount of zooming brings the molecules back, while their chemical structures keep being drawn by a separate handler that was never detached. That is exactly the reported symptom, and I hit it directly during this work. It is now a durable class, .trivial.always-visible, with the stale inline value cleared first.

Verified on the URL from #150 (R-HSA-975634, flag=class:Complex!drug): flagged → opacity 1 at zoom 0.25, 0.5 and 1.5; unflagged → 0, 0.5, 1, so the normal fade is untouched. Still correct after navigating to another pathway with the flag active.

Since both reports describe this as intermittent ("sometimes, but not always"), please re-check on beta.reactome.org and close if it looks right.