The height is bigger than the viewport.

If there are toolbars docked at the left or right, the right toolbar is hidden due to larger width. 


You can fix a bit the width by using this code:

<telerik:RadEditor ID="RadEditor1" runat="server" RenderMode="Lightweight" OnClientCommandExecuted="OnClientCommandExecuted">
    <Tools>
        <telerik:EditorToolGroup>
            <telerik:EditorTool Name="AjaxSpellCheck" />
        </telerik:EditorToolGroup>
        <telerik:EditorToolGroup dockingzone="Left">
            <telerik:EditorTool Name="AjaxSpellCheck" />
        </telerik:EditorToolGroup>
        <telerik:EditorToolGroup dockingzone="Right">
            <telerik:EditorTool Name="ToggleScreenMode"></telerik:EditorTool>
        </telerik:EditorToolGroup>
    </Tools>
</telerik:RadEditor>

<script>
    function OnClientCommandExecuted(editor, args) {
        if (args.get_commandName() === "ToggleScreenMode" && editor.isFullScreen()) {
            var editorId = editor.get_id();
            var editorElm = editor.get_element();
            var leftToolbar = $telerik.$(editorElm).find("#" + editorId + "Left.reToolBarWrapper");
            var rightToolbar = $telerik.$(editorElm).find("#" + editorId + "Right.reToolBarWrapper");

            var widthExcess = leftToolbar.width() + rightToolbar.width();

            if (widthExcess) {
                editorElm.style.width = (parseInt(editorElm.style.width) - widthExcess) + "px";
            }
        }
    }
</script>

When an input of type text is selected user cannot change its properties from Design mode. 

Workaround: 

<telerik:RadEditor runat="server" ID="RadEditor1">
    <Content>
        <input type="text" style="width: 100px; height: 22px;" />
        <br />
        
        <textarea></textarea>
    </Content>
</telerik:RadEditor>

<script>
    Telerik.Web.UI.RadEditor.prototype.getSelectedElement = function (range) {
        var editor = this;
        var contentArea = editor.get_contentArea();
        var $ = $telerik.$;
        var $Editor = Telerik.Web.UI.Editor;
        var utils = $Editor.Utils;

        if (editor.get_renderMode() === Telerik.Web.UI.RenderMode.Mobile) {
            var highlighted = $(contentArea).find(".__reTextHighlight,.__reNodeHighlight");
            if (highlighted.length) {
                var first = highlighted.get(0);
                var last = highlighted.last().get(0);
                return first === last ? first :
                    utils.findCommonAncestor(first, last);
            }
        }

        range = range || editor.getDomRange();
        if (!range) {
            var activeElement;
            try {
                activeElement = editor.get_document().activeElement;
            } catch (ex) { return undefined; }
            return $(activeElement).is('input[type=text],input[type=password],textarea') ?
                activeElement : undefined;
        }

        var container = range.commonAncestorContainer;
        if (container === contentArea || $.contains(contentArea, container)) {
            var selectedNode = $Editor.RangeEdges.commonNode(range);
            var isTextNode = utils.isTextNode(selectedNode);

            return utils.isTextNode(selectedNode) ? selectedNode.parentNode : selectedNode;
        }
    };
</script>

It should rather select the last cell of the table. 

For the time being you can use the following workaround:
		<telerik:RadEditor ID="RadEditor1" runat="server" ></telerik:RadEditor>
		<script>
			var oldExecute = Telerik.Web.UI.Editor.InsertLinkCommand.prototype.onExecute;

			Telerik.Web.UI.Editor.InsertLinkCommand.prototype.onExecute = function () {
				this.linkProperties.href = encodeURI(this.linkProperties.href);
				oldExecute.call(this);
			}
		</script>

RadEditor in Fullscreen mode appears cut off at the right and at the bottom. 



In order to fix that, you can add this CSS rule to the page:

<style>
    .RadEditor.reFullScreen {
        box-sizing:border-box;
    }
</style>

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

You can workaround this issue by resetting the content area's height only for IE:

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

<script>
    function OnClientLoad(editor, args) {
        if ($telerik.isIE) editor.get_contentArea().style.height = "auto";
    }
</script>

When a partially copied table is pasted into the Editor in Chrome, it is pasted wrapped in the folloing div, making it not visible:

<div class="telerik_paste_container" style="border-width: 0px; position: absolute; overflow: hidden; margin: 0px; padding: 0px; left: 3px; top: 215px; width: 1px; height: 1px;">
...
</div>


Steps to reproduce:
1. Open http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx
2. Clear the contents of the editor
3. Insert a table (any configuration of rows and columns) 
4. Go to a new line
5. Type a word on the new line
6. Select the word and a partial amount of the inserted table
7. Copy
8. Paste
9. Navigate to the HTML browser of the editor
10. Observe the "telerik_paste_container" still wrapping the pasted content

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

<script type="text/javascript">
	var editorPrototype = Telerik.Web.UI.RadEditor.prototype;
	var onAfterPaste = editorPrototype._onAfterPaste;
	editorPrototype._onAfterPaste = function (range, tmpPasteContainer) {
		try {
			onAfterPaste.call(this, range, tmpPasteContainer);
		} catch (e) { }
		$telerik.$(this.get_contentArea()).find(".telerik_paste_container").remove();
	};
</script>

Currently we are in the process of securing our web sites. we are experiencing issue on Xhtml Validator in RadEditor where it is not properly loading due to mixed content issue. There is no way to redirect to HTTPS instead of HTTP site.

We can reproduce this on Rad Editor Demo site by making site as HTTPS and click on XHTML Validator icon.

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

Could you please add that feature?

This issue can be reproduced when there is some initial HTML content entered that cause scroll to appear. Next, adding some new lines and having a mechanism to call the get_html(true) method would scroll the content area to a random position and cause flickering.

The exact steps to reproduce are:

1. Use RadEditor in http://localdemos.telerik.com/aspnet-ajax-dev/editor/examples/overview/defaultcs.aspx
2. Add this HTML:
        <p>start</p>
        <p>&nbsp;</p>
        <p>end</p>

3. Go to Design;
4. Select from the empty paragraph (<p>&nbsp;</p>) to the end of text (<p>end</p>);
5. Copy via Ctrl+C;
6. Try to paste at the end of the "end" paragraph.

You can workaround this issue by using this override:

<telerik:RadEditor runat="server" ID="RadEditor1">
    <Content>
        <br/>
        <iframe src="about:blank">Iframe not supported</iframe>
    </Content>
</telerik:RadEditor>

<script>
    Telerik.Web.UI.Editor.Utils._copyElementsBetweenNodes = function (oldNode, newNode, elementName)
    {
        var oldElements = oldNode.getElementsByTagName(elementName);
        var newElements = newNode.getElementsByTagName(elementName);
        for (var i = 0; i < oldElements.length; i++)
        {
            switch (elementName)
            {
                case "script":
                case "title":
                    newElements[i].text = oldElements[i].text;
                    break;
                case "style":
                    if (newElements[i].innerHTML != oldElements[i].innerHTML)
                    {
                        newElements[i].styleSheet.cssText = oldElements[i].styleSheet.cssText;
                    }
                    break;
                case "select":
                    newElements[i].selectedIndex = oldElements[i].selectedIndex;
                    break;
                case "input":
                    if ((oldElements[i].type == 'radio' || oldElements[i].type == 'checkbox') && $telerik.$(oldElements[i]).attr("checked"))
                    {
                        $telerik.$(newElements[i]).attr("checked", "checked");
                        if ($telerik.isIE9Mode && oldElements[i].type == 'checkbox' && oldElements[i].checked)
                        {
                            newElements[i].checked = true;
                            newElements[i].setAttribute("checked", "checked");
                        }
                    }
                    break;
                case "iframe":
                    var innerHTML = oldElements[i].innerHTML;
                    if (innerHTML)
                    {
                        var outerHTML = newElements[i].outerHTML;
                        if (outerHTML)
                        {
                            var gtIndex = outerHTML.indexOf(">");
                            if (gtIndex > 0)
                            {
                                outerHTML = outerHTML.substr(0, gtIndex) + ">" + innerHTML + outerHTML.substr(gtIndex + 1 + innerHTML.length);
                                newElements[i].outerHTML = outerHTML;
                            }
                        }
                    }
                    break;
                default:
                    if (newElements[i].innerHTML != oldElements[i].innerHTML)
                        $E.Utils.setElementInnerHtml(newElements[i], oldElements[i].innerHTML);
                    break;
            }
        }
    };
</script>

For example, using this markup:

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

and this Page_Init code:

protected void Page_Init(object sender, EventArgs e)
{
    RadEditor1.RenderMode = RenderMode.Lightweight;
}

Causes icons to either miss or their position is incorrect.

It becomes the operation of Chrome only.

after the new line, if you type continuously double-byte character string "あい",the input result was "い".
The correct answer is "あい".

For operation that does not occur in earlier versions, I think I've considered this release version of the bug, the cause can be identified?

The Paste event is added twice to the Editor's undo stack in IE. The issue is reproducible as of Q3 2013.

Steps to reproduce:
1. Open http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx
2. Paste some content

Result: The Paste command is added two time in the Undo stack

The content is not scrolled to the end of the pasted content in IE11 - the scrollbar keeps its initial position instead. The issue is reproducible in IE (tested in IE11) and Chrome, but not in Firefox nor standard editable iframe.

Steps to reproduce:
1. Open in IE: http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx
2. Paste big enough content, so the scrollbar will be shown

Actual: The scrollbar stays on the top.
Expected: The content area is scrolled to the end of the pasted content

Possible workaround could be creating a temporary selectable element after the pasted content, which to be selected manually:
		<telerik:RadEditor ID="txtMessage"  runat="server" OnClientPasteHtml="OnClientPasteHtml">
		</telerik:RadEditor>
		<script>
			function OnClientPasteHtml(editor, args) {
				if (args.get_commandName() == "Paste" && $telerik.isIE) {
					args.set_value(args.get_value() + "<div id='selectableEl'></div>");
					setTimeout(function () {
						var selectedEl = editor.get_document().getElementById("selectableEl");
						console.log(editor.getSelectedElement());
						Telerik.Web.UI.Editor.Utils.scrollTo(selectedEl, editor);
						$telerik.$(selectedEl).remove();
					}, 0);
				}
			}
		</script>

In scenarios where RadEditor is moved through the DOM the typical approach is to call the onParentNodeChanged method in order to re-render the editor. In Edge browser this does not work. CleanAtributes filter is alerted as failed and further RadEditor is unresponsive. 

Temporary solution is to switch the content area mode to DIV:

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

Using plain RadEditor controls with default Default toolbar where ToolProvideID is also used, a JS error is thrown and ToolProvide mechanism does not operate as expected. 

As a temporary workaround, you can use any other toolbar mode (e.g., ShowOnFocus).