Hi, I wrote a resize function that invalidates texture, resizes the device and changes the window-size, and at the end restores the textures. But if i call the function that windows which are in the background of my window are not redrawed and so if my window gets smaller, you can see the last rendered frame of my old window. Does anyone have a solution?

yes i have used the clear-function.

my resizing function is:

int CMyDirect3D::Resize3DEnvironment( RECT rcClient, RECT rcBounds )
{
HRESULT hr;

// Restore the Device Objects with the function that is saved
// in this function-pointer.
if( MYDIRECT3D_OK != lpfnInvalidDeviceObject( ) )
return MYDIRECT3D_INVALIDDEVOBJFAILED;

RECT rcClientOld;
rcClientOld = m_rcWindowClient;

// Update window properties
m_rcWindowBounds = rcBounds;
m_rcWindowClient = rcClient;

if( rcClientOld.right - rcClientOld.left !=
m_rcWindowClient.right - m_rcWindowClient.left ||
rcClientOld.bottom - rcClientOld.top !=
m_rcWindowClient.bottom - m_rcWindowClient.top )
{
// A new window size will require a new backbuffer
// size, so the 3D structures must be changed accordingly.

m_d3dpp.BackBufferWidth = m_rcWindowClient.right - m_rcWindowClient.left;
m_d3dpp.BackBufferHeight = m_rcWindowClient.bottom - m_rcWindowClient.top;

// Resize the 3D environment
// Reset the device
if( FAILED( hr = m_pd3dDevice->Reset( &m_d3dpp ) ) )
{
DisplayErrorMsg( D3DAPPERR_RESIZEFAILED, MYDIRECT3D_NONE );
return MYDIRECT3D_RESIZE3DENVFAILED;
}

// Store render target surface desc
LPDIRECT3DSURFACE8 pBackBuffer;
m_pd3dDevice->GetBackBuffer( 0, D3DBACKBUFFER_TYPE_MONO, &pBackBuffer );
pBackBuffer->GetDesc( &m_d3dsdBackBuffer );
pBackBuffer->Release();
}

// Restore the Device Objects with the function that is saved
// in this function-pointer.
if( MYDIRECT3D_OK != lpfnRestoreDeviceObject( ) )
return MYDIRECT3D_RESTOREDEVOBJFAILED;

return MYDIRECT3D_OK;
}

yes i think that`s right. i think i ask this question in the winapi forum.