REPRO
Run the snippet below
Inspect the DOM (at the beginning of the form you will see the .rtbSlide element)
Click the toolbar button to invoke an ajax request
actual: the .rtbSlide element is multiplied with every request
expected: the toolbar is fully disposed
<asp:UpdatePanel runat="server">
<ContentTemplate>
<telerik:RadToolBar RenderMode="Lightweight" ID="RadToolBar1" runat="server"
AutoPostBack="true">
<Items>
<telerik:RadToolBarButton Text="postback to test">
</telerik:RadToolBarButton>
</Items>
</telerik:RadToolBar>
</ContentTemplate>
</asp:UpdatePanel>
WORKAROUND
<script>
var oldDispose = Telerik.Web.UI.RadToolBar.prototype.dispose;
Telerik.Web.UI.RadToolBar.prototype.dispose = function()
{
if (this._moreButtonDropDown && typeof this._moreButtonDropDown.dispose == 'function') {
this._moreButtonDropDown.dispose();
}
oldDispose.call(this);
}
</script>