- First, Render_opengl inherits from Hook_event, thus Render_opengl should not re-declare members of Hook_event that are already protected, like _core.
 - Second, force Core to wait until the QT engine has initialized the Open GL windows before loading the files. Do this the quick and dirty way by inserting an event loop in the middle of the LAUNCH_INTERFACE case of Core, until initializeGL() has been called.