# AUR6003 ## Error Message `AUR6003: Scroller info is readonly and cannot be modified.` ## Description This error occurs when code attempts to mutate scroller information that the virtualization system treats as readonly (internal state used for measurement and scheduling). ## Example Trigger This is most commonly triggered by directly modifying internal virtualization/scroller state from custom code or a custom integration. ## Correct Usage * Treat virtualization internals as readonly. * Use public APIs/configuration options (or supported extension points) instead of mutating internal scroller info objects. ## Troubleshooting * Search for code that assigns to scroller/virtual-repeat internal properties (for example in custom strategies or wrappers). * If you need custom behavior, prefer implementing a supported strategy/adapter rather than mutating internal state. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.aurelia.io/developer-guides/error-messages/ui-virtualization/aur6003.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.