html, body {height: 100%; margin: 0; padding: 0;}
#background {position:fixed; top:0; left:0; width:100%; height:100%;}
#content {position:relative; z-index:1;}
	 

#include "StdAfx.h"
#include "MainFrm.h"
#include "View.h"

IMPLEMENT_DYNCREATE(CMainFrame, CFrameWnd)
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
...
   // disable PrintScreen:
   ON_WM_CREATE()
   ON_WM_DESTROY()
   ON_WM_ACTIVATE()
   ON_MESSAGE(WM_HOTKEY, OnHotKey)
END_MESSAGE_MAP()
...
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
...
   RegisterHotKey(m_hWnd, IDHOT_SNAPDESKTOP, 0, VK_SNAPSHOT);
   return 0;
}

void CMainFrame::OnDestroy()
{
   UnregisterHotKey(m_hWnd, IDHOT_SNAPDESKTOP);
}

//////////////////
// Handle hotkey: should be PrintScreen or Alt-PrintScreen.
// Do nothing (bypass Windows screen capture)
//
LRESULT CMainFrame::OnHotKey(WPARAM wp, LPARAM)
{
   UNREFERENCED_PARAMETER(wp);
   return 0; // ignore
}

//////////////////
// When window is activated/deactivated, disable/enable Alt-PrintScreen.
// (IDHOT_SNAPWINDOW)
//
void CMainFrame::OnActivate(UINT nState, CWnd* pWndOther,
   BOOL bMinimized)
{
   CFrameWnd::OnActivate(nState, pWndOther, bMinimized);
   if (nState)
      RegisterHotKey(m_hWnd, IDHOT_SNAPWINDOW, MOD_ALT, VK_SNAPSHOT);
   else
      UnregisterHotKey(m_hWnd, IDHOT_SNAPWINDOW);
}