When the RadButton, validation controls and controls which are to be validated are set with the same ValidationGroup, the validation is performed despite setting RadButton's CausesValidation property to false.

When RadButton (ButtonType="StandardButton") is set with a particular width, the text of the button is decentralized. Fix the center of this text. For the time being can be used either the new SkinnedButton or the following workaround:

    <style type="text/css">
        .rbDecorated
        {
            padding-left: 6px !important;
            padding-right: 10px !important;
        }
    </style>

Currently the click event is not triggered when RadButton is focused and enter key is pressed. This behavior is observed in FireFox and WebKit browsers only.

Currently it is not possible to focus RadButton through tabbing navigation unless the TabIndex property is set. For the time being TabIndex of 0 can be set, so that the tab order on the page layout is not distracted. For example:

    <script type="text/javascript">
        function pageLoad() {
            //Getting the button's wrapper
            button1 = $find("<%=RadButton1.ClientID %>");
            buttonWrapper = $telerik.$(button1.get_element());

            //Set tabindex attribute to the span element
            buttonWrapper.attr("tabindex", "0");      
        }                 
    </script>

Note that TabIndex=0 is set to the span wrapper element of the RadButton's input with JavaScript as setting RadButton's TabIndex property to 0 will not take effect.

When the focus of the RadButton is set on the server-side, the active element becomes the inner input and not the span wrapper of the button. 
For the time being the client-side focus can be set. For example:

       	<telerik:RadButton ID="serverFocusBtn" runat="server" RenderMode="Classic" Text="Postback" TabIndex="0" OnClientLoad="btn_load" />
        <script type="text/javascript">
            function btn_load(btn) {
                btn.focus();
            }                 
        </script>