For a quick fix we could change proxy auth prompts to always use window prompts. This would regress a little bit on UX, but proxy auth is more of an edge case than basic auth triggered by websites. Also I'd assume most proxies to not require authentication for every site visit.
Bug 1698991 Comment 10 Edit History
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For a quick fix we could change proxy auth prompts to always use window prompts. This would regress a little bit on UX, but proxy auth is more of an edge case than basic auth triggered by websites. Also I'd assume most proxies do not require authentication for every site visit.