Only getting one pixel of a texture [Windows]

[Mikmacer]

For my project I need to create a plugin for Unity3D to render into an another window the exact same thing than the in-game rendering of the editor.

I use the same OpenGL context than unity, however the window context is different.

I use the GetNativeTextureID() in the Unity c# environment to get the texture ID. In the C++ plugin code a full screen textured quad is draw show the texture into the plugin generated window.

My problem is that I can only see one pixel of the texture. I was wondering which states of OpenGL could cause that? Maybe it's because I use a different OpenGL version?

Thats my OpenGL code:

Thanks for any help =)

                // Start Rendering into the plugin window
		window->setContextToWindow();
 
 
		glViewport(0,0, config->getWidth(), config->getHeight() );
 
		glEnable(GL_TEXTURE_2D);
		glDisable(GL_LIGHTING);
		glDisable(GL_CULL_FACE);
 
		glClearColor( 0.5f, 0.5f, 0.5f, 0.0f );
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		glDisable(GL_DEPTH_TEST);
 
		glMatrixMode(GL_TEXTURE);
		glLoadIdentity();
 
		glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		gluOrtho2D(-1.0f,1.0f,-1.0f,1.0f);
 
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
 
		glBindTexture(GL_TEXTURE_2D, textureIndex_);
 
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
		glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
		glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 
 
		glPushMatrix();
 
 		glBegin( GL_QUADS );
 			//glColor3f(1.0f,1.0f,1.0f);
 			glTexCoord2d(0.0f, 0.0f);glVertex2f( -1.0f, -1.0f );
 			glTexCoord2d(1.0f, 0.0f);glVertex2f( 1.0f, -1.0f );
 			glTexCoord2d(1.0f, 1.0f);glVertex2f( 1.0f, 1.0f );
 			glTexCoord2d(0.0f, 1.0f);glVertex2f( -1.0f, 1.0f );
 		glEnd();
		glPopMatrix();
 
		if (!SwapBuffers( window->getHdc() ))
		{
			int error = GetLastError();
			cout << "Cant swap buff: " << error << endl;
		}
 
		// Continue rendering into the Unity Editor
		window->setContextToExtern();