Problem
In #1763640: Followup: Introduce config context to make original config and different overrides accessible @pounard rightly points out that by implementing the global config overrides as a context rather than an event listener, once you enter a different context, the global config overrides are not used anymore. Eg. if you enter a user specific context, your global overrides are no more. Previously global config overrides were implemented as a config event listener, so they reacted on config events like other overrides. Keeping that behavior would have let global overrides coexist with language specific overrides. That was certainly a point we missed with the original patch. By implementing global overrides as a context, going into a different context also assumed to solve "no overrides applied", while that is not actually what is happening. The config events are still firing and language specific overrides will still apply nonetheless.
Proposal
1. Move global config overrides back to an event listener, like the locale config event listener still is.
2. Modify the override-free context to either (a) make no config override-related events fire or (b) place an indicator into the context to tell listeners to not perform their overrides or (c) something even more clever.