   what to reset after losing focus in a fullscreen application?
  is resetting d3d device enough or should I reload every texture, model, shaders etc?   
  All i know is that you have to reload sprites and fonts (i'm a beginner)You can do that like this:D3dSprite->OnLostDevice(); // Tells Direct3DSprite that d3ddev has been  // Lost and to release the memory of the sprited3ddev->Reset(&d3dpp);// resets d3ddevD3dSprite->OnResetDevice();// Reaquires the sprite memory;  You have to recreate all D3DPOOL_DEFAULT resources. They need to be released prior to reset, and then created again post-reset.Turn on Direct3D debug output in the DirectX control panel, and then watch the 'Output' window in your debugger when you reset the device. It'll tell you if there are resources that you still need to release when you reset.   