For the time being the following workaround can be used.

JavaScript:

    <script>
        function pageLoad() {
            var chart = $find("<%=RadHtmlChart1.ClientID%>");
            chart._chartObject.options.categoryAxis.axisCrossingValue = [0, 3];
            chart.repaint();
        }
    </script>
ASPX:

        <telerik:RadHtmlChart ID="RadHtmlChart1" runat="server" Width="600px" Height="400px">
            <PlotArea>
                <Series>
                    <telerik:ColumnSeries AxisName="axis1">
                        <SeriesItems>
                            <telerik:CategorySeriesItem Y="30" />
                            <telerik:CategorySeriesItem Y="20" />
                            <telerik:CategorySeriesItem Y="10" />
                        </SeriesItems>
                    </telerik:ColumnSeries>
                    <telerik:ColumnSeries AxisName="axis2">
                        <SeriesItems>
                            <telerik:CategorySeriesItem Y="3100" />
                            <telerik:CategorySeriesItem Y="2700" />
                            <telerik:CategorySeriesItem Y="1400" />
                        </SeriesItems>
                    </telerik:ColumnSeries>
                </Series>
                <XAxis AxisCrossingValue="2">
                    <Items>
                        <telerik:AxisItem LabelText="item 1" />
                        <telerik:AxisItem LabelText="item 2" />
                        <telerik:AxisItem LabelText="item 3" />
                    </Items>
                </XAxis>
                <YAxis Name="axis1">
                </YAxis>
                <AdditionalYAxes>
                    <telerik:AxisY Name="axis2"></telerik:AxisY>
                </AdditionalYAxes>
            </PlotArea>
        </telerik:RadHtmlChart>

Currently, controls that have popups can have their z-index controlled as explained here: http://www.telerik.com/help/aspnet-ajax/controlling-absolute-positioning-with-zindex.html

RadComboBox has an explicit ZIndex property. Should all controls with popup elements have such a property?

Please update stylebuilder to match up with latest controls.. there is no skin generated yet for tilelist and lightbox. also last update Q3 2013 doesnt include default skin files in telerik's folder. where i could download base skin files of telerik?

Allow persisting of column widths
Allow persisting of what columns are displayed when a user selects them. (via EnableHeaderContextMenu) 

Thanks