Although I've only seen this on Windows I imagine it is something common for all environments.
We know that we can not access the user interface from a thread. If we do we raise a runtime exception (here is this text taken from Language Reference: Thread):
Do not access any built-in property or method of a user interface control or Window from within a Thread as platform UI frameworks are not thread-safe. Doing so raises a ThreadAccessingUIException. See below for additional information.
However if you try some OpenGL.method from a thread, you get no Exception but that method is not executed. at least when you refresh the OpenGLSurface, there is nothing that was done from a thread. So, be careful because you get no warning, but the result is not the one expected.