Ext:RowLayout和ColumnLayout连用必须加panel的问题

<ext:RowLayout ID="RowLayout1" runat="server" Split="false">
<Rows>
<ext:LayoutRow RowHeight=".5">
<ext:Panel runat="server">
<Items>
<ext:ColumnLayout ID="ColumnLayout1" runat="server" Split="false" FitHeight="true">
<Columns>
<ext:LayoutColumn ColumnWidth=".5">
<ext:Panel ID="Panel7" runat="server" Border="false" ColumnWidth=".5">
<Content>
<div id="colRealContrast">
</div>
</Content>
</ext:Panel>
</ext:LayoutColumn>
<ext:LayoutColumn ColumnWidth=".5">
<ext:Panel ID="Panel8" runat="server" Border="false" ColumnWidth=".5">
<Content>
<div id="pieRealContrast">
</div>
</Content>
</ext:Panel>
</ext:LayoutColumn>
</Columns>
</ext:ColumnLayout>
</Items>
</ext:Panel>
</ext:LayoutRow>
<ext:LayoutRow RowHeight=".5">
<ext:Panel runat="server">
<Items>
<ext:ColumnLayout ID="ColumnLayout2" runat="server" Split="false" FitHeight="true">
<Columns>
<ext:LayoutColumn ColumnWidth=".5">
<ext:Panel ID="Panel10" runat="server" Border="false" ColumnWidth=".5">
<Content>
<div id="colRiseContrast">
</div>
</Content>
</ext:Panel>
</ext:LayoutColumn>
<ext:LayoutColumn ColumnWidth=".5">
<ext:Panel ID="Panel11" runat="server" Border="false" ColumnWidth=".5">
<Content>
<div id="pieRiseContrast">
</div>
</Content>
</ext:Panel>
</ext:LayoutColumn>
</Columns>
</ext:ColumnLayout>
</Items>
</ext:Panel>
</ext:LayoutRow>
</Rows>
</ext:RowLayout>

<ext:LayoutRow RowHeight=".5">下不加panel时，会提示错误