UI would sometimes disappear with the Metal backend.
This occured in situations where there was only a single
GPUContext within a single GHOST window, meaning
the activation routine for the context was never run.
Context activation is required to ensure the backbuffer
was up to date upon resize. Otherwise, re-sizing the
window would cause the screen to turn grey as the
new drawables would not be rendered to.
Authored by Apple: Michael Parkin-White
Co-authored-by: Michael Parkin-White <mparkinwhite@apple.com>
Pull Request: https://projects.blender.org/blender/blender/pulls/119299
3c25b079ce