The issue is due to failing recalculation logic of the iframe content area. 

To resolve the issue you can use a RadEditor control with ContentAreaMode="Div" to render the content area as a DIV element, instead iframe.  

If the iframe mode is needed, you can use the following workaround to fix the content cell and the iframe appearance. 

<telerik:RadEditor ID="RadEditor1" runat="server" height="50px" OnClientLoad="OnClientLoad">
	<Tools>
		<telerik:EditorToolGroup>
			<telerik:EditorTool Name="Bold" />
			<telerik:EditorTool Name="Italic" />
			<telerik:EditorTool Name="Underline" />
		</telerik:EditorToolGroup>
	</Tools>
</telerik:RadEditor>

<script type="text/javascript">
	function OnClientLoad(editor, args) {
		setTimeout(function () {
			var editorIframe = editor.get_contentAreaElement(),
				originalIframeHeight = editorIframe.offsetHeight,
				contentCell = editorIframe.parentNode,
				cellSize = contentCell.offsetHeight,
				isCellSmaller = (originalIframeHeight - cellSize) > 2;
		
			if (isCellSmaller) {
				contentCell.style.height = originalIframeHeight + "px";
			}
		}, 0);
	}
</script>

Such functionality would improve the user experience for UI interaction of the end-users with the RadEditor tools.

Such behavior can be achieved using the following customization with the RadEditor control:

<telerik:RadEditor ID="RadEditor1" runat="server" OnClientLoad="OnClientLoad">
</telerik:RadEditor>
<script>
    function OnClientLoad(editor, args) {
        editor.attachEventHandler("onkeyup", function (e) {
            if (e.keyCode == 27)
            {
                closeContextMenus(editor.get_toolAdapter()._contextMenus);
            }
        })
    }

    function closeContextMenus(contextMenus) {
        for (var menu in contextMenus) {
            contextMenus[menu].hide();
        }
    }
</script>

The problem is when not tracked content does not exist. User cannot set the cursor outside the tracked content.
Although, typing should split the tracked text and user should be able to type in not tracked text when the feature is disabled.

I think you may consider the following similar type of control(s) in future release.  I think the following is a good fit for use between a BI solution and standard reports.  It gives regular users some flexibilities to generate ad-hoc queries within an application.

http://demo.easyquerybuilder.com/asp-net-ajax/

In case where RadButton is set as DefaultButton to the form or a panel and should trigger validation it does not PostBack the page regardless if the page is valid or not

Button single click becomes disabled permanently if a validation error is detected. After satisfying the validator conditions the button doesn't get enabled and it is not possible to post back the page.

This issue happens only under IE11 with IE9 compatibility mode. Using real IE9 browser the area is rendered correctly.

You should be aware of this issue when testing cross browser functionality of the RadEditor. 

With the current implementation if the RenderMode is set to Auto in the web.config file it is later automatically changed to Leightweight instead of Mobile.

When the editor is loaded with a full HTML page editable document, which contains nested tables with images inside, selecting an image causes the Chrome browser to break. 

Possible workaround is disabling the resize widget of the tables and images in Chrome by incorporating this sample code:

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

<script type="text/javascript">
    Telerik.Web.UI.RadEditor.prototype._initializeResizableWidget =
        function myfunction() { };
</script>

This bug causes incorrect user behavior. Lists cannot be disconnected with Enter, in some cases user cannot add multiple empty paragraphs. 

For the time being you can resolve the issue by incorporating the following JS code block:

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

<script type="text/javascript">
    var setCursorFn = Telerik.Web.UI.Editor.Utils._setCursorInNode;
    Telerik.Web.UI.Editor.Utils._setCursorInNode = function (cursorElement, container, editor) {
        setCursorFn.call(this, cursorElement, container, editor);
        if ($telerik.isChrome) {
            var selection = editor.getSelection();
            var range = selection.getRange();
            if (!range.collapsed) {
                range.collapse();
                selection.selectRange(range);
            }
        }
    }
</script>

This is the popular image zoom control used in many sites like amazon.com to display a zoomed selection of an image in another panel or window.

The issue with incorrectly counted header elements comes due to the reason that the main table considers the TH elements as child elements no matter if they are nested in a second table.

You can find attached a simple project with the fixed AccessibleTable dialog set as external.

Navigate to:

http://localdemos.telerik.com/aspnet-ajax/treelist/examples/databinding/loadondemand/defaultcs.aspx

1) Expand item with ID:2, then items: id:1413, id:1414

2)Expand item id:1

3)Fill Item ID textbox with "303" and Level textbox with "2"

4)Click "ExpandItemToLevel"

5)The icon of item 304 seems like "expanded"(and it should be), however the item is not expanded.

When a user works with large content in the editor and pastes a word in the end of it, the page and content area are scrolled to the top. This causes an inconvenience for the editing behavior, the user should scroll down to continue typing or editing.