Mozilla lost the z-index or/and the image, (inside a div) that i repeat for the whole screen, some times, not always.

    LOAD THE IMAGE WITH VB.NET

  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  height: auto;
  width: auto;
  z-index: 5000;
  background: url(images/Loader_overlay.png);

Development problem witth css. <div id="divLoaderHidden" style="position: relative; display: none; text-align: center; vertical-align: middle; height: 600px; z-index: 8000;"> <div id="divHotelLoader" style="text-align: center; vertical-align: middle; height: 60px;"> <img id="imgGifLoader" runat="server" src="" alt="Searching ... " style="margin: auto;" /> </div> <div id="divAdvLoader" runat="server" style="text-align: center; vertical-align: middle; height: 500px;"> '' LOAD THE IMAGE WITH VB.NET </div> </div> <div id="divOverlayLoader" style="display: none;"> </div> #divOverlayLoader { position: fixed; top: 0; bottom: 0; left: 0; right: 0; height: auto; width: auto; z-index: 5000; background: url(images/Loader_overlay.png); }