Dispose ONLY the custom-LUT colormap texture cache.
Custom LUTs are scene/dataset-scoped. SceneLoader.dispose()
calls this on dataset unload so unused custom textures don't
accumulate across many dataset switches in a long-lived app.
Built-ins are not touched.
Dispose ONLY the custom-LUT colormap texture cache.
Custom LUTs are scene/dataset-scoped. SceneLoader.dispose() calls this on dataset unload so unused custom textures don't accumulate across many dataset switches in a long-lived app. Built-ins are not touched.