This issue causes inconvenience among users. Block elements in the content cannot be edited properly when used in the RadEditor.

You can workaround this problem by overriding the setActive method of the RadEditor's object:

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

<script type="text/javascript">
	Telerik.Web.UI.RadEditor.prototype.setActive = function () {
		var $T = Telerik.Web.UI;

		if (this._emptyMessageContainer) this._hideEmptyMessage();

		if ($telerik.isIE && this.getSelection().isControl()) return;

		var curArea = this.get_mode() == $T.EditModes.Html ? this._getTextArea() : this.get_contentArea();

		if ($telerik.isIE) {
			var activeElement = this.get_document().activeElement;
			if ((activeElement && activeElement == curArea) ||
			$telerik.$.contains(curArea, activeElement)) {
				return;
			}
		}

		if (curArea && curArea.setActive) curArea.setActive();
	};
</script>