Flex 4.5 - s:Window - s:DataGrid - Memory Leak?

Question

Hi All,
We're trying to clean up Air windows and noticing some odd behaviour.
Here is the case:
We have a spark window that contains a spark datagrid, this datagrid is bound to a dataprovider which is a model in the main application.
When we close the window, there is ALWAYS one instance of MyWindow that remains in memory.
And looking at the trace of the window does not give much information...
Has anyone seen this before? Alex, you've helped us a lot before with memory issues, can you shed some light please?
Thank-you!
We have a simple test case: ( Didn't wire the close handler, so make sure to use the close button.)
Main.mxml
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication
          xmlns:mx="library://ns.adobe.com/flex/mx"
          xmlns:fx="http://ns.adobe.com/mxml/2009"
          xmlns:s="library://ns.adobe.com/flex/spark"
          xmlns:domain="domain.*"
          >
            <fx:Script>
                    <![CDATA[
                              import mx.core.Window;
                              public var window:MyWindow;
                              protected function openWindow(event:MouseEvent):void {
                                        window = new MyWindow();
                                        window.model = this.model;
                                        window.open();
                              protected function closeWindow(event:MouseEvent):void {
                                        window.close();
                                        window = null;
                    ]]>
          </fx:Script>
          <fx:Declarations>
                     <domain:Model
                              id="model"
                              />
          </fx:Declarations>
          <s:HGroup>
                    <s:Button
                              label="Open"
                              click="openWindow(event)"
                              />
                    <s:Button
                              label="Close"
                              click="closeWindow(event)"
                              />
          </s:HGroup>
</s:WindowedApplication>
Model.as
package domain {
           import mx.collections.ArrayCollection;
          [Bindable]
          public class Model {
                      public var collection:ArrayCollection = new ArrayCollection([ { name:'Adobe' }, { name:'Apple' } ]);
MyWindow.mxml
<?xml version="1.0" encoding="utf-8"?>
<s:Window
          xmlns:mx="library://ns.adobe.com/flex/mx"
          xmlns:fx="http://ns.adobe.com/mxml/2009"
          xmlns:s="library://ns.adobe.com/flex/spark"
          width="400"
          height="300"
          >
          <fx:Script>
                    <![CDATA[
                              import domain.Model;
                              [Bindable]
                              public var model:Model;
                    ]]>
          </fx:Script>
          <s:DataGrid
                    dataProvider="{ model.collection }"
                    />
</s:Window>

Answer 1

Hi Alex,
We've tested with this and discovered that any datagrid in a spark window assigned a dataprovider results in always one instance of the window staying in memory.
Here is what we tested:
Window with nothing in it = gets collected.
Window with datagrid and no dataprovider = gets collected.
Window with datagrid and no dataprovider but "model" is passed from main = gets collected.
window with datagrid and local dataprovider (inline) = get pinned.
window with datagrid and passed "model" as dataprovider = get pinned.
Tested this on two computers with FB 4.5.1
Thanks again!
I cannot see where I can post fxp sorry. So I am posting code adjustments here showing the window with just inline dp.
Modified MyWindow.mxml:
<?xml version="1.0" encoding="utf-8"?>
<s:Window
          xmlns:mx="library://ns.adobe.com/flex/mx"
          xmlns:fx="http://ns.adobe.com/mxml/2009"
          xmlns:s="library://ns.adobe.com/flex/spark"
          width="400"
          height="300"
          >
            <s:DataGrid id="dataGrid">
                    <s:ArrayCollection>
                              <s:DataItem key="1000" name="Abrasive" price="100.11" call="false"/>
                              <s:DataItem key="1001" name="Brush" price="110.01" call="true"/>
                              <s:DataItem key="1002" name="Clamp" price="120.02" call="false"/>
                              <s:DataItem key="1003" name="Drill" price="130.03" call="true"/>
                              <s:DataItem key="1004" name="Epoxy" price="140.04" call="false"/>
                              <s:DataItem key="1005" name="File" price="150.05" call="true"/>
                              <s:DataItem key="1006" name="Gouge" price="160.06" call="false"/>
                              <s:DataItem key="1007" name="Hook" price="170.07" call="true"/>
                              <s:DataItem key="1008" name="Ink" price="180.08" call="false"/>
                              <s:DataItem key="1009" name="Jack" price="190.09" call="true"/>            
                    </s:ArrayCollection>
          </s:DataGrid>
  </s:Window>
Modified main.mxml
<?xml version="1.0" encoding="utf-8"?>
<s:WindowedApplication
          xmlns:mx="library://ns.adobe.com/flex/mx"
          xmlns:fx="http://ns.adobe.com/mxml/2009"
          xmlns:s="library://ns.adobe.com/flex/spark"
          xmlns:domain="domain.*"
          >
            <fx:Script>
                    <![CDATA[
                              import mx.core.Window;
                              public var window:MyWindow;
                              protected function openWindow(event:MouseEvent):void {
                                        window = new MyWindow();
                                        window.open();
                              protected function closeWindow(event:MouseEvent):void {
                                        window.close();
                                        window = null;
                    ]]>
          </fx:Script>
            <fx:Declarations>
                      <domain:Model
                              id="model"
                              />
            </fx:Declarations>
            <s:HGroup>
                    <s:Button
                              label="Open"
                              click="openWindow(event)"
                              />
                    <s:Button
                              label="Close"
                              click="closeWindow(event)"
                              />
          </s:HGroup>
  </s:WindowedApplication>