QOpenGLShaderProgram OpenGL3.3 and ARB tessellator

[elmcati]

The configuration is of a linux or Windows OS with a Nvidia graphic card limited to OpenGL 3.3 hence without the Tesssellator shader except via the ARB extension. The extension is supported by the driver.
The shader works fine with a graphic card supporting OpenGL 4+. In order to provide a fallback on a system with the ARB, the shader is outfitted with the usual enable ARB extension for the tessellation control shader and tessellation evaluator shader
#extension GL_ARB_tessellation_shader : enable

When trying to compile the source (tcs/tes) via QOpenGLShaderProgram I am getting as error that the ARB extension is not supported. QOpenGLShaderProgram tries to compile a different type of shader ????

Anybody with a similar issue?

Thanks