Add the following to the page that is producing the SlickGrid.

<style>
html, body {
  margin: 0;
  padding: 0;
  background-color: white;
  overflow: auto
;}

body {
  font: 11px Helvetica, Arial, sans-serif
;}

.fill_browser {
  position: absolute;
  top: 40px;
  left: 0;
  right: 0;
  bottom: 0
;}
</style>

<div id="#MyGrid" class="fill_browser"></div>