The basic concept of having a realizable grid is you need to remove all the fixed width that you set in your grid. You can then use percent instead(%) of pixels (px) when setting the size of your grid. And finally, you can use client-side plugin such as jQuery realizable to handle that for you.
For example you can define your HTML markup like this:
<div id="datalist" style="width:550px;">
<!--
</div
And then use jQuery resizable like this:
<script type="text/javascript">
$(function() {
$("#datalist").resizable();
})
</script>
More info, see:
Resizable | jQuery UI[
^]
PS: There may be some here who knows about Telerik controls, but I believed you stand a better chance by posting it at Telerik dedicated forums:
https://www.telerik.com/forums/kendo-ui/grid