i have to problem with rendering context.
iam using DGLOpengl Header and i found some Sample code.
and i am create Redering context with this code. its Render to a Tpanel

Code:
    FDC:=GetDC(fChwnd);


    InitOpenGL;
    fpfd.dwFlags := PFD_DRAW_TO_WINDOW OR PFD_SUPPORT_OPENGL OR PFD_DOUBLEBUFFER;
    SetPixelFormat ( fDC, ChoosePixelFormat ( fDC, @fpfd ), @fpfd );
    fhlgrc:=wglCreateContext ( fDC );
    ActivateRenderingContext( fDC, fhlgrc, TRUE );
    fStart := GetTickCount;
    fElapsedTime:=1;
    //load simple glsl shader
    fglslsimpleprog := TGLSLProgram.Create();
    fglslsimplevert := TGLSLShader.Create('Resources\Shaders\simple.vert');
    fglslsimplefrag := TGLSLShader.Create('Resources\Shaders\simple.frag', GL_FRAGMENT_SHADER_ARB);
    fglslsimpleprog.Attach(fglslsimplevert);
    fglslsimpleprog.Attach(fglslsimplefrag);
    fglslsimpleprog.Link;
    fglslsimpleprog.Enable;
    fglslsimpleprog.Set2F('resolution',fwidth*2,fheight*2);
when Docking or unDocking i call this this code
Code:
    fpaint:=false;
    fglslsimpleprog.Disable;


    DeactivateRenderingContext;
    ReleaseDC(fChwnd, fDC);
    fchwnd:=hwnd;
    fdc:=GetDC(FChwnd);
    InitOpenGL;
    fpfd.dwFlags := PFD_DRAW_TO_WINDOW OR PFD_SUPPORT_OPENGL OR PFD_DOUBLEBUFFER;
    SetPixelFormat ( fDC, ChoosePixelFormat ( fDC, @fpfd ), @fpfd );
    fhlgrc:=wglCreateContext ( fDC );
    ActivateRenderingContext( fDC, fhlgrc, TRUE );
    fglslsimpleprog.Enable;
    fpaint:=true;
while Panel Docking There isnt any Problem. But When Undock this Panel its not Render on Panel

What is wrong i dont understand . How i should change rendering Context ?