When the NewLineMode of a RadEditor is set to Div and a line of text is entered in an empty content area of the control under Chrome, the text will be wrapped in a paragraph element.

Possible workaround is to set an initial content with a DIV and BR elements inside:

<telerik:RadEditor runat="server" ID="RadEditor1" NewLineMode="Div">
    <Content>
        <div></div>
    </Content>
</telerik:RadEditor>

Another possible solution is incorporating the following JS code right after the RadEditor declaration:

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

<script type="text/javascript">
	Telerik.Web.UI.RadEditor.prototype._onKeyPressed = function (e) {

	}
</script>