https://bugs.winehq.org/show_bug.cgi?id=42324
--- Comment #8 from Rastafabi f.platte@platte-web.de --- (In reply to Ken Thomases from comment #4)
In Apple's terminology, the context changes which "virtual screen" is active for the context. In theory, a Mac app should note when the context's virtual screen changes, re-query the GL extensions and limits, and reconfigure its rendering pipeline accordingly.
This might very well be theory because in reality I never came across an application which re-querys it's pipeline. All games benchmarks and GL-heavy applications I tested ran way better if launched on the external eGPU powers screen even if they were moved to the internal one afterwards.