Flex 4 - Can not get ADG working

Question

Hello,
I have just downloaded flex 4 SDK (flex_sdk_4.0.0.14159_mpl) and Flash Builder 4.
I have created a test prroject and can not get it working with Advanced Data Grids.
Here is my set up:  Created Project called Test, this contains one MXML file that contains an Advanced Data Grid:
<fx:Script>
        <![CDATA[
            import mx.collections.HierarchicalData;
            [Bindable] private var _test:HierarchicalData;
        ]]>
</fx:Script>
<mx:AdvancedDataGrid id="test" dataProvider="{_test}">
   <mx:columns>
       <mx:AdvancedDataGridColumn headerText="COL_A" />               
       <mx:AdvancedDataGridColumn headerText="COL_B" />               
       <mx:AdvancedDataGridColumn headerText="COL_C" />               
    </mx:columns>
</mx:AdvancedDataGrid>
This works Okay.  I then include a libary into the project, the libary, also built with the same SDK, contains a class that contains nothing but one single method that does nothing:
<mx:Canvas xmlns:fx="http://ns.adobe.com/mxml/2009"
           xmlns:s="library://ns.adobe.com/flex/spark"
           xmlns:mx="library://ns.adobe.com/flex/mx"
           width="100%" height="100%">
    <fx:Script>
        <![CDATA[
            import mx.controls.advancedDataGridClasses.AdvancedDataGridColumn;
            private function test(col:AdvancedDataGridColumn):void { }
        ]]>
    </fx:Script>
</mx:Canvas>
Launcing now causes the error
TypeError: Error #1007: Instantiation attempted on a non-constructor.
    at mx.controls::AdvancedDataGridBaseEx/getSeparator()[E:\dev\4.0.0\frameworks\projects\datav isualization\src\mx\controls\AdvancedDataGridBaseEx.as:4618]
    at mx.controls::AdvancedDataGridBaseEx/createHeaderSeparators()[E:\dev\4.0.0\frameworks\proj ects\datavisualization\src\mx\controls\AdvancedDataGridBaseEx.as:4660]
    at mx.controls::AdvancedDataGrid/createHeaderSeparators()[E:\dev\4.0.0\frameworks\projects\d atavisualization\src\mx\controls\AdvancedDataGrid.as:2428]
    at mx.controls::AdvancedDataGridBaseEx/drawSeparators()[E:\dev\4.0.0\frameworks\projects\dat avisualization\src\mx\controls\AdvancedDataGridBaseEx.as:4574]
    at mx.controls::AdvancedDataGridBaseEx/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\ datavisualization\src\mx\controls\AdvancedDataGridBaseEx.as:2119]
    at mx.controls::AdvancedDataGrid/updateDisplayList()[E:\dev\4.0.0\frameworks\projects\datavi sualization\src\mx\controls\AdvancedDataGrid.as:2899]
    at mx.controls.listClasses::AdvancedListBase/validateDisplayList()[E:\dev\4.0.0\frameworks\p rojects\datavisualization\src\mx\controls\listClasses\AdvancedListBase.as:3468]
    at mx.managers::LayoutManager/validateDisplayList()[E:\dev\4.0.0\frameworks\projects\framewo rk\src\mx\managers\LayoutManager.as:663]
    at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.0.0\frameworks\projects\frame work\src\mx\managers\LayoutManager.as:718]
    at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.0.0\frameworks\projec ts\framework\src\mx\managers\LayoutManager.as:1072]
Removing the method in the libary project alivates the problem.  But I can not see why this is a problem in the first place!!??!?!?!?!?!?!?
Can anyone help. this is really weird.

Answer 1

I'm getting the same error. This is due to a bug in AdvancedDataGridBaseEx.  The offending code is:
            var headerSeparatorClass:Class =
                getStyle("headerSeparatorSkin");
            sepSkin = new headerSeparatorClass();
if getStyle returns null then you will be trying to instantiate  headerSeparatorClass is going to cause the "Instantiation attempted on a non-constructor" error.
Apparently someone thought that the headerSeparatorSkin would never be null.