In IE the command works fine.

In FF the command is always disabled.

In Chrome is always enabled, but using it do not affect the content.

If you need this tool to be always disabled under Chrome, you can use the following approach to disable the tool:

<telerik:RadEditor runat="server" ID="RadEditor1" OnClientSelectionChange="OnClientSelectionChange">
</telerik:RadEditor>

<script type="text/javascript">
	function OnClientSelectionChange(sender, args) {
		if ($telerik.isChrome) {
			setTimeout(function () {
				sender.get_toolAdapter().getToolByName("AbsolutePosition").set_enabled(false);
			},0)
		}
	}
</script>