GeoLeaf Core API - v3.0.0
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    _activationRequest: number = 0

    Monotonically increasing ticket taken by every ACTIVATION REQUEST reaching setBaseLayer() — distinct from _styleGeneration, which counts style APPLICATIONS (_applyViaStyleChange and the WMTS path).

    Exists because an activation can be DEFERRED: when the style is not loaded, setBaseLayer re-arms itself on the map's idle event, capturing its key in the closure. Nothing made that closure notice it had been superseded, so the boot basemap could re-apply itself on top of a basemap the user had since chosen — measured at R.7b on the tourism profile: positron applied, then ~500 ms later the map silently snapped back to terrain-terrarium, and the layer labels were destroyed by the round trip without being rebuilt. No error was logged on either side.

    _styleGeneration could not serve here: a deferred request that never applies anything does not move it, so a stale deferral would still pass its own check.