diff --git a/libsrc/grabber/x11/X11Grabber.cpp b/libsrc/grabber/x11/X11Grabber.cpp
index 494af111..c817fadc 100644
--- a/libsrc/grabber/x11/X11Grabber.cpp
+++ b/libsrc/grabber/x11/X11Grabber.cpp
@@ -17,98 +17,114 @@ X11Grabber::X11Grabber(int cropLeft, int cropRight, int cropTop, int cropBottom,
     _x11Display(nullptr),
     _screenWidth(0),
     _screenHeight(0),
+    _croppedWidth(0),
+    _croppedHeight(0),
     _image(0,0)
 {
     _imageResampler.setHorizontalPixelDecimation(horizontalPixelDecimation);
     _imageResampler.setVerticalPixelDecimation(verticalPixelDecimation);
-    _imageResampler.setCropping(0, 0, 0, 0); // cropping is performed by XGetImage
+    _imageResampler.setCropping(0, 0, 0, 0); // cropping is performed by XShmGetImage
 }
 
 X11Grabber::~X11Grabber()
 {
     if (_x11Display != nullptr)
     {
+	freeResources();
         XCloseDisplay(_x11Display);
     }
 }
 
-int X11Grabber::open()
+void X11Grabber::freeResources()
 {
-    const char * display_name = nullptr;
-    _x11Display = XOpenDisplay(display_name);
+    // Cleanup allocated resources of the X11 grab
+    XShmDetach(_x11Display, &_shminfo);
+    XDestroyImage(_xImage);
+    shmdt(_shminfo.shmaddr);
+    shmctl(_shminfo.shmid, IPC_RMID, 0);
+}
 
+void X11Grabber::setupResources()
+{
+    _xImage = XShmCreateImage(_x11Display, _windowAttr.visual,
+                _windowAttr.depth, ZPixmap, NULL, &_shminfo,
+                _croppedWidth, _croppedHeight);
+    
+    _shminfo.shmid = shmget(IPC_PRIVATE, _xImage->bytes_per_line * _xImage->height, IPC_CREAT|0777);
+    _shminfo.shmaddr = _xImage->data = (char*)shmat(_shminfo.shmid,0,0);
+    _shminfo.readOnly = False;
+    
+    XShmAttach(_x11Display, &_shminfo);
+}
+
+bool X11Grabber::Setup()
+{
+    _x11Display = XOpenDisplay(NULL);
     if (_x11Display == nullptr)
     {
-        std::cerr << "Failed to open the default X11-display" << std::endl;
-        return -1;
-    }
+      std::cerr << "Unable to open display";
+      if (getenv("DISPLAY"))
+	std::cerr <<  " " << std::string(getenv("DISPLAY")) << std::endl;
+      else
+	std::cerr << ". DISPLAY environment variable not set" << std::endl;
+      return false;
+     }
+     
+    _window = DefaultRootWindow(_x11Display);
 
-    return 0;
-}
+    return true;
+ }
 
 Image<ColorRgb> & X11Grabber::grab()
 {
-    if (_x11Display == nullptr)
-    {
-        open();
-    }
-
-    updateScreenDimensions();
-    
-    Xscreen = DefaultScreenOfDisplay(_x11Display);
-
-    const unsigned croppedWidth  = _screenWidth - _cropLeft - _cropRight;
-    const unsigned croppedHeight = _screenHeight - _cropTop - _cropBottom;
-    
-    xImage = XShmCreateImage(_x11Display,   DefaultVisualOfScreen(Xscreen),
-				  DefaultDepthOfScreen(Xscreen),
-				  ZPixmap, NULL, &shminfo,
-				  croppedWidth, croppedHeight);
-    
-    shminfo.shmid = shmget(IPC_PRIVATE, xImage->bytes_per_line * xImage->height, IPC_CREAT|0777);
-    shminfo.shmaddr = xImage->data = (char*)shmat(shminfo.shmid,0,0);
-    shminfo.readOnly = False;
-    
-    XShmAttach(_x11Display, &shminfo);
-
-    // Capture the current screen
-    XShmGetImage(_x11Display, DefaultRootWindow(_x11Display), xImage, _cropLeft, _cropTop, 0x00FFFFFF);
-    if (xImage == nullptr)
+    XShmGetImage(_x11Display, _window, _xImage, _cropLeft, _cropTop, 0x00FFFFFF);
+    if (_xImage == nullptr)
     {
         std::cerr << "Grab failed" << std::endl;
         return _image;
     }
 
-    _imageResampler.processImage(reinterpret_cast<const uint8_t *>(xImage->data), xImage->width, xImage->height, xImage->bytes_per_line, PIXELFORMAT_BGR32, _image);
-
-    // Cleanup allocated resources of the X11 grab
-    XShmDetach(_x11Display, &shminfo);
-    XDestroyImage(xImage);
-    shmdt (shminfo.shmaddr);
-    shmctl(shminfo.shmid, IPC_RMID, 0);
+    _imageResampler.processImage(reinterpret_cast<const uint8_t *>(_xImage->data), _xImage->width, _xImage->height, _xImage->bytes_per_line, PIXELFORMAT_BGR32, _image);
 
     return _image;
 }
 
 int X11Grabber::updateScreenDimensions()
 {
-    XWindowAttributes window_attributes_return;
-    const Status status = XGetWindowAttributes(_x11Display, DefaultRootWindow(_x11Display), &window_attributes_return);
+    const Status status = XGetWindowAttributes(_x11Display, _window, &_windowAttr);
     if (status == 0)
     {
         std::cerr << "Failed to obtain window attributes" << std::endl;
         return -1;
     }
 
-    if (_screenWidth == unsigned(window_attributes_return.width) && _screenHeight == unsigned(window_attributes_return.height))
+    if (_screenWidth == unsigned(_windowAttr.width) && _screenHeight == unsigned(_windowAttr.height))
     {
         // No update required
         return 0;
     }
+    
     std::cout << "Update of screen resolution: [" << _screenWidth << "x" << _screenHeight <<"] => ";
-    _screenWidth  = window_attributes_return.width;
-    _screenHeight = window_attributes_return.height;
+
+    if (_screenWidth || _screenHeight)
+      freeResources();
+    
+    _screenWidth  = _windowAttr.width;
+    _screenHeight = _windowAttr.height;
+    
     std::cout << "[" << _screenWidth << "x" << _screenHeight <<"]" << std::endl;
+    
+    if (_screenWidth > unsigned(_cropLeft + _cropRight))
+      _croppedWidth  = _screenWidth - _cropLeft - _cropRight;
+    else
+      _croppedWidth  = _screenWidth;
+    
+    if (_screenHeight > unsigned(_cropTop + _cropBottom))
+      _croppedHeight = _screenHeight - _cropTop - _cropBottom;
+    else
+      _croppedHeight = _screenHeight;
+    
+    setupResources();
 
     return 0;
 }