Hi Chet
We've done some digging and what's happening is this:
- The plugin's openGL rendering is happily drawing stuff
- The host starts to remove the plugin's NSView from the screen in preparation for deleting it
- Deep in the Apple NSView code, it realises that an OpenGLView is being removed from the screen, so it frees the GL resources associated with it
- Our plugin's render thread is still busily doing GL stuff at this point, and has no idea the view is being hidden, so its GL calls start to fail, and the assertion is triggered
TBH I don't think the assertions are actually a problem in this case. The OSX GL calls seem to be thread-safe and although they fail to draw, that's actually ok because the window is off-screen, and everything survives if you ignore (or disable) the assertions.