Made IsContextLost automatically set the flag by checking with the emscripten WebGL wrapper + added a LOT of logging messages right before throwing ErrorCode_BadSequenceOfCalls exceptions + increased the http request timeouts from 60 to 600 sec (big datasets in some recent customer use cases) + added IsContext lost through the Viewport/Context layer (to make it reachable from external API) + the same for the underlying device context (for debug)

--- a/Framework/OpenGL/OpenGLShader.cpp	Fri Aug 16 16:24:11 2019 +0200
+++ b/Framework/OpenGL/OpenGLShader.cpp	Wed Aug 21 16:16:30 2019 +0200
@@ -127,6 +127,7 @@
       }
       else
       {
+        LOG(ERROR) << "OpenGLShader::Release(): (!isValid_)";
         throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
       }
     }