When a SingleClick RadButton is clicked and its AutoPostBack property is set to false its disabled state as well as the optional text from the SingleClickText property are persisted. For the time being the SingleClick functionality can be set on the client. For example:
ASPX:
		<script type="text/javascript">
			function DoSubscriptionValidation(button, args) {
				var isPostBack = window.confirm("Perform postback?");
				button.set_autoPostBack(isPostBack);
				if (isPostBack) {
					button.set_singleClick(true);
					button.set_singleClickText("Please Wait");
					button.click();
				}
			}
		</script>
		<telerik:RadButton ID="RadButton1" runat="server" Text="Click"
			OnClick="OnClick1" OnClientClicking="DoSubscriptionValidation" />
C#:
	protected void OnClick1(object sender, EventArgs e)
	{
		System.Threading.Thread.Sleep(2000);
	}

Important: The issue only occurs when the Buttons are spread around in different rows in RadGrid. 
When multiple RadButtons (ButtonType="ToggleButton" ToggleType="Radio") are grouped through GroupName property, the server-side property checked doesn't take effect when the button which is to be checked is declared before the current checked button.

The workaround is to execute JavaScript from the server which sets the checked property. For example:

C#:

        string script = "function f(){$find(\"" + RadButton1.ClientID + "\").set_checked(true); Sys.Application.remove_load(f);}Sys.Application.add_load(f);";
        ScriptManager.RegisterStartupScript(this, this.GetType(), "key", script, true);

An error is thrown when RadButton NavigateUrl is defined in content page with tilde and the master page is up one level.

Workaround: Remove the tilde from the navigate url.

This is a duplicate of http://feedback.telerik.com/Project/108/Feedback/Details/210060, see there for a workaround and for status updates.


You can change the DPI settings in Windows from the Display Settings. Setting a size of 125% and clicking on a button will throw a server exception:


-------

Input string was not in a correct format.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.FormatException: Input string was not in a correct format.

Source Error: 
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 
[FormatException: Input string was not in a correct format.]
   System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +12526913
   System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +120
   Telerik.Web.UI.RadImageButton.LoadPostData(String postDataKey, NameValueCollection postCollection) +256
   Telerik.Web.UI.RadWebControl.System.Web.UI.IPostBackDataHandler.LoadPostData(String postDataKey, NameValueCollection postCollection) +16
   System.Web.UI.Page.ProcessPostData(NameValueCollection postData, Boolean fBeforeLoad) +457
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1833

Reproduction:

<telerik:RadButton ID="RadButton1" runat="server" Text="Submit" EnableEmbeddedSkins="false" EnableEmbeddedBaseStylesheet="false"/>
<telerik:RadCheckBox ID="RadCheckBox1" runat="server" Text="CheckBox" Skin="Default" />

Workaround:

<telerik:RadButton ID="RadButton1" runat="server" Text="Submit" Skin=""/>

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>

When a RadButton with a PostBackUrl property set is located inside an UpdatePanel,  it does not redirect to the PostBackUrl on click and a JavaScript error message is thrown.

The workaround is to use:

- Either a RadButton (ButtonType="LinkButton") and set its NavigateUrl to the desired page that is to be redirected
   
-OR a RadButton (ButtonType="StandardButton") and use its OnClientClicking event handler to cancel the postback and redirect to the desired page through window.location.href. For example:

    <script type="text/javascript">
        function OnClientClicking(sender, args) {

            window.location.href = "http://www.bing.com";
            args.set_cancel(true);

        }
    </script>

A JavaScript error is thrown when a button with AutoPostback enabled on the client-side is clicked in IE.

Note: The error is thown only when the AutoPostback is enabled in the ClientClicked event handle, but not in ClientClicking.

JavaScript error:
SCRIPT5007: Unable to get property 'controlState' of undefined or null reference
File: ScriptResource.axd, Line: 658, Column: 38