A workaround is to disable animations. You can do this in the control markup/code-behind or JavaScript depending on your case.
In case this is not an option, you can disable the animations prior to closing so that autosizing does not use them:
function CloseAndRebind() {
GetRadWindow().BrowserWindow.refreshGrid();
setTimeout(function () {
var wnd = GetRadWindow();
wnd.set_animation(0);//disable animations
wnd.close();
}, 0);
}
You can find the detailed discussion here http://www.telerik.com/forums/issue-with-radwindow-(2014-2-618-45)