The following code sample creates a Portal with two columns (one 70% width the other 30%). If you start by dragging "Portlet 1" to the right side column it will be correctly resized to 30% width. However, if you now drag it back to the left side column it will remain at 30%instead of being resized back to 70%. However, if you drag a second Portlet over to the left side column, they will both be resized to 70%.

<ext:Portal ID="Portal1" runat="server" Border="false" Stateful="true">
 <Content>
  <ext:ColumnLayout ID="ColumnLayout1" runat="server">
  
   <ext:LayoutColumn ColumnWidth=".70">
    <ext:PortalColumn 
     ID="PortalColumn1" 
     runat="server" 
     StyleSpec="padding:10px 0 10px 10px">
     <Content>
      <ext:AnchorLayout ID="AnchorLayout1" runat="server">
       <ext:Anchor Horizontal="100%">
        <ext:Portlet ID="Portlet1" Title="Portlet 1" runat="server"/>
       </ext:Anchor>
      </ext:AnchorLayout>
     </Content>
    </ext:PortalColumn>
   </ext:LayoutColumn>
   
   <ext:LayoutColumn ColumnWidth=".30">
    <ext:PortalColumn 
     ID="PortalColumn2" 
     runat="server" 
     StyleSpec="padding:10px 0 10px 10px">
     <Content>
      <ext:AnchorLayout ID="AnchorLayout2" runat="server">
       <ext:Anchor Horizontal="100%">
        <ext:Portlet ID="Portlet2" Title="Portlet 2" runat="server"/>
       </ext:Anchor>
      </ext:AnchorLayout>
     </Content>
    </ext:PortalColumn>
   </ext:LayoutColumn>
   
  </ext:ColumnLayout>    
 </Content>
</ext:Portal>