Fixes Black Desert Online launcher showing black screen only (after switch to EGL backend). The specifics of the launcher (which is using GL directly for a part of its rendering process) is that it will do SwapBuffers always after setting current context to NULL. This behaviour was once causing problems with GLX GL backend as well but was fixed by eb5993a7c6fbc1cd9deac0dceabc8f1c76e14ba8. Now with default EGL backend all the Wine logic related to SwapBuffers works, except for eglSwapBuffers() doesn't swap anything if there is no current context or current context is not the one which is associated with the surface. That is the same with Mesa and NVidia drivers. That is different from glxSwapBuffers which doesn't have any deal with the context. This patch makes the launcher render properly (while to avoid a crash in libcef that currently misses font files and can be worked around with 'winetricks corefonts'). -- https://gitlab.winehq.org/wine/wine/-/merge_requests/10033#note_128833