In the ImageManager when using AsyncUpload as the upload manager control, the uploaded image is not selected. This prevents a fluent workflow of upload and insert of the image.

The image preview should react in a contextual way when deleting the image as well. Then the previewer should stay empty as is the case with a first load of the dialog.

Inline commands such as bold, italic, underline doesn't trigger each time with empty selection in Internet Explorer.

The current content filters of the RadEditor control supports XHTML content, in which attributes should have a proper value. Although with HTML5 the browsers started supporting boolean attributes that could be used without any type of value.

Such attributes are being stripped or replaced, which at some point leads to an incorrect behavior if the user's HTML code.

It would be useful if developers could have the ability to modify this behavior and generate correct HTML5 code.

A possible usage of such attributes is when they are used as XHTML5 valid attributes, with the proper value (e.g. disabled="disabled").

i am looking for an example how to handle an uploaded screenshot with the radeditor.
it is a great feature, one reason why i took telerik, but i can't find the documentation for that.
do you have a link where i can look it up ?

The area shapes in Image Map Editor dialog couldn't be moved or resized in Internet Explorer 11.

When ToolbarMode is set to "RibbonBarFloating" the RadEditor height becomes greater than the control height. As a result the wrapper overlaps with the elements box below.

As a temporary workaround for ToolbarMode="RibbonBarFloating" only, the following JavaScript code need to be applied on the page:

   <script type="text/javascript">
            (function () {
                var getToolbarHeight = Telerik.Web.UI.Editor.UI.DimensionsCalculator.prototype._getToolbarHeight;
                Telerik.Web.UI.Editor.UI.DimensionsCalculator.prototype._getToolbarHeight = function (container) {
                    var $container = $telerik.$(container);
                    $container.append($container.find("div"));
                    return getToolbarHeight.call(this, container);
                }
            })();
</script>

Update: 

For securing the RadEditor content and preventing XSS attacks we advise enabling the RemoveScripts, EncodeScripts, StripCssExpressions and StripDomEventAttributes content filters to sanitize the content. For more information please check the following help article and blog post on the matter:
Prevent Cross-site Scripting (XSS)
Securing RadEditor Content and Preventing XSS Attacks.
 
Original message:
It is possible to conduct a successful XSS attack by injecting a specific malicious content in the RadEditor content. This attack targets Internet explorer browsers. It takes advantage of a security vulnerability related to the CSS expression rule in Legacy IE browsers, where arbitrary JavaScript code embedded in the style attribute of a DOM element can be run on the page.

There is a workaround that is strongly recommended to be used in order to make such attack attempts unsuccessful. The idea is to strip the expression declaration from the style attribute value of DOM elements in the RadEditor Content. Following is a sample implementation

Usage:

protected void Page_Load(object sender, EventArgs e)
{
	var sanitizer = new CssExpressionSanitizer();
	theEditor.Content = sanitizer.Sanitize(theEditor.Content);
}




Content of the CssExpressionSanitizer class:

public class CssExpressionSanitizer
{
	private static readonly Regex expressionPattern = new Regex(@"<[a-zA-Z0-9]+[^>]*?style=['""]?.*?(?<cssRule>[^;""]+: expression(?<bracket>\())", RegexOptions.Compiled);

	public string Sanitize(string input)
	{
		var matches = expressionPattern.Matches(input);
		for (int i = matches.Count - 1; i >= 0; i--)
		{
			input = SanitizeExpression(input, matches[i]);
		}

		return input;
	}

	private string SanitizeExpression(string input, Match m)
	{
		var cssRuleIndex = m.Groups["cssRule"].Index;
		var expressionIndex = m.Groups["bracket"].Index;

		input = StripMatchingBracketsWithContent(input, expressionIndex);
		input = input.Remove(cssRuleIndex, expressionIndex - cssRuleIndex);

		if (input[cssRuleIndex] == ';')
		{
			input = input.Remove(cssRuleIndex, 1);
		}

		return input;
	}

	private string StripMatchingBracketsWithContent(string input, int startIndex)
	{
		var openBrackets = 0;
		do
		{
			char currentChar = input[startIndex];
			if (currentChar == '"' || currentChar == '\'' || currentChar == '/')
			{ //strip within quotation marks making sure brackets appearing in string constructs do not interfere with the counting
				var parser = new InPairStringParser(currentChar);
				input = parser.Sanitize(input, startIndex);

				currentChar = input[startIndex];
			}
			input = input.Remove(startIndex, 1);

			if (currentChar == '(')
				openBrackets++;
			else if (currentChar == ')')
				openBrackets--;
		}
		while (openBrackets > 0 && input.Length > startIndex);

		return input;
	}

	public class InPairStringParser
	{
		public InPairStringParser(char pairChar)
		{
			this.pattern = new Regex(String.Format("{0}.*?(?<!\\\\){0}", pairChar));
		}

		public string Sanitize(string input, int startIndex)
		{
			var subinput = input.Substring(startIndex);

			return input.Substring(0, startIndex) + pattern.Replace(subinput, "", 1);
		}

		private readonly Regex pattern;
	}
}

When using the Flash Manager to add a flash object into the content, causes the HTML mode to be non editable. 

The following example code is a possible workaround for this behavior:

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

<script type="text/javascript">
    function OnClientModeChange(editor, args) {
        var $ = $telerik.$,
            mode = editor.get_mode(),
            contentAreaElement = editor.get_contentArea(),
            editorModes = Telerik.Web.UI.EditModes;

        if (mode === editorModes.Html) {
            $(contentAreaElement).hide();
        } else {
            $(contentAreaElement).show();
        }
    }
</script>

Currently, if a paragraph has altered line-height in MS Word, pasting it into the RadEditor results to a normal paragraph with not affection to the line-height CSS property. 

Provide ability to easily obtain Markdown syntax from the RadEditor, to be saved on disk. Ex. string RadEditor.GetMarkdown()

RadEditor produces invalid HTML when nesting lists in IE11 and IE10.

The validation error is: UL element cannot be nested within element UL

Setting invalid content into RadEditor leads to unexpected behavior such as content getting lost in certain situations.

http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx

1. Delete the content and create a list
2. Press Enter several times

Expected: The list is interrputed
Actual: The list cannot be interrupted

In MS Word, if the entire list item is selected, changing the font-size will change the character's formatting too. While selecting only a text node (e.g., without highlighting) will not apply formatting to the list item.

In the RadEditor there is no option to somehow control the size of the bullet points. The only way is the user to switch to HTML mode and manually add font-size attribute in the <li> element.

It would be nice if there is a possibility to change the formatting similar to the editing experience in MS Word.

If a list with some non-default formatting in the bullet points is pasted, the custom formatting is not applied.

For example, changing the font-size of a bullet point in MS Word list, will be pasted only with relevant formatting in the text node, but will leave the <li> elements stripped out.

It would be nice if there is additional logic to apply the proper formatting in the bullet points accordingly to the one copied from MS Word.

Commonly users add empty anchor elements, e.g, <p><a name="anchor"></a>Some text</p>. By that, they provide a proper anchoring behavior in HTML, and prevent the text from being decorated as link.

The limitation here is that the anchor element cannot be selected, and thus unable to be edited via the LinkManager dialog.

It would be nice, if there is some built-in logic that handles this situation and provide a proper way for the end-users to be able to visually distinguish this anchors and edit them if needed.

You can find attached  a custom solution for such approach.

Currently, this command switches from Design to HTML mode and vise versa when EditType="Inline".

In Normal editing mode this tool is disabled in the HTML mode and cannot be used, although it is useful and provides yet another layout option for the default look of the RadEditor.

You can test the additional layout option by running this example:

<telerik:RadEditor runat="server" ID="RadEditor1"
    EditModes="Design" OnClientModeChange="OnClientModeChange">
    <Tools>
        <telerik:EditorToolGroup>
            <telerik:EditorTool Name="Bold" />
            <telerik:EditorTool Name="ToggleEditMode" />
        </telerik:EditorToolGroup>
    </Tools>
</telerik:RadEditor>

<script type="text/javascript">
    function OnClientModeChange(sender, args) {
        setTimeout(function () {
            sender.get_toolAdapter().getToolByName("ToggleEditMode").set_enabled(true);
        },0)
    }
</script>

This tool can be redesigned to be available in the HTML mode in all cases not only when Inline editing mode is enabled.

A possible workaround is to set the import step after all other rules in the CssFile of the RadEditor. CssFile would look like:

.h1
{
    background-color: Aqua;
}
.div
{
    color: Green;
}
@import url(StyleSheet.css);

A JavaScript error is thrown when a hidden AccessibleRadEditor is loaded in IE 10. The error message is:

"SCRIPT5007: Unable to get property 'get_element' of undefined or null reference "

Code to reproduce the issue:

        <asp:Button ID="btn1" runat="server" Text="Show Editor" OnClientClick="showEditor(); return false" />
        <div id="div1" style="display: none">
            <telerik:AccessibleRadEditor ID="AccessibleRadEditor1" runat="server" ></telerik:AccessibleRadEditor>
        </div>
        <script>
            function showEditor() {
                $telerik.$("#div1").show();
            }
        </script>