The Window will not open in the center of the screen if it was already opened once and the page has been scrolled. It seems that the Window keeps opening at the same position initially was opened, hence it could open out of screen bounds.
Code
<style>
.mydiv {
margin: 2000px 100px;
}
</style>
<telerik:RadWindow ID="RadWindow1" runat="server">
<ContentTemplate>
<h3>RadWindow1 Content</h3>
</ContentTemplate>
</telerik:RadWindow>
<script>
function ShowEditForm(sender, args) {
var wnd = $find("<%= RadWindow1.ClientID %>");
wnd.show();
}
Sys.Application.add_load(function () {
setTimeout(function () {
$telerik.$('.mydiv')[0].scrollIntoView();
}, 100)
});
</script>
<div class="mydiv">
<telerik:RadButton runat="server" ID="RadButton1" Text="OpenWindow" AutoPostBack="false" OnClientClicked="ShowEditForm" />
</div>