Some a11y instantiators might query for interfaces that we don't support. Unfortunately they have to start a11y to make those queries. If we added a filter to LazyInstantiator's QueryInterface, we could preemptively return E_NOINTERFACE on those ones that we know for sure we do not support. We could also add telemetry for any QIs that forced instantiation but were for unsupported interfaces.
I'd like to see this fixed. I wonder if anyone not Aaron can help?
3 months ago
I don't have the cycles for this myself but I'll keep on eye on it. I also don't have any free hands on the team right now.
I'd be indeed curious to see a percent of accessibility instantiations by clients requesting unsupported interfaces. I'm not sure though about a technical side here, iirc WM_GETOBJECT always returns IAccessible interface, which assumes accessibility is running.