When you copy a table from MS Excel and you paste it in the RadEditor under Chrome, an image that depicts the copied table will be inserted in the content area of the control along with the table.

You can use the following workaround to avoid inserting an image with the table:

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

        <script type="text/javascript">
            var getImages = Telerik.Web.UI.Editor.ClipboardImagesProvider.prototype.getImages;
            Telerik.Web.UI.Editor.ClipboardImagesProvider.prototype.getImages = function (event) {
                var images = getImages.call(this, event);
                debugger;
                if (event.clipboardData && images.length && event.clipboardData.getData("text/html")) {

                    return [];
                }

                return images;
            };
        </script>