From Stephan Huber, added reset of _currentContext when graphics context is closed.
From Stephan Huber, added reset of _currentContext when graphics context is closed.


stmh/osg,stmh/osg,omega-hub/osg,XiaoCC/osg,ghub/osg,omega-hub/osg,artoolkit/osg,ntoand/osg,ghub/osg,koshman86/osg,ghub/osg,XiaoCC/osg,omega-hub/osg,koshman86/osg,artoolkit/osg,XiaoCC/osg,artoolkit/osg,omega-hub/osg,XiaoCC/osg,XiaoCC/osg,stmh/osg,stmh/osg,ntoand/osg,ntoand/osg,koshman86/osg,ntoand/osg,koshman86/osg,ghub/osg,stmh/osg,artoolkit/osg