flex <mx:List> is hidden by other UI component - apache-flex

Question

In flex UI, my <mx:list> can not be shown completely because of other component shelterring (for example: the refresh button shelter part of it ). How can I make the <mx:list> in front of all other UI component.
This is my code:
<s:HGroup verticalAlign="middle">
<s:Label text="Choose Log File"/>
<mx:ComboBox id ="logFileChooseCombo" dataProvider="{fileNameList}" width="150" color="0x000000"
close="changeLogFilesHandler(event);"/>
<mx:Spacer width="320" />
<s:Label text="Filter or HighLight:" />
<mx:ComboBox id ="filterChooseCombo" dataProvider="{filterOrHighlight}" width="150" color="0x000000"/>
<s:VGroup height="25">
<s:TextInput id="logContentInput" change="filterLogContent()"
enabled="true"
focusIn="clearMyTextInput()"
text="Filter/HightLight"
width="250" height="26"/>
**<mx:List id="searchMsgList"** x="65" y="35" width="200" height="200" fontSize="12"
change="itemChangEvent(event);" />
</s:VGroup>
</s:HGroup>
</mx:Canvas>
<s:HGroup verticalAlign="middle">
<s:Label text="Filter By Log Level:"/>
<mx:ComboBox id ="logLevelCombo" dataProvider="{logLevelsInt}" width="150" color="0x000000"
close="changeLogLevelHandler(event);"/>
<s:CheckBox id="showStack" click="showStackTrace(event)" selected="false"/>
<s:Label text="show stackTraces"/>
<mx:Spacer width="550" />
<s:Button id="test" label="refresh2">
</s:Button>
</s:HGroup>

Answer 1

You have a lot going on, with a mix of nested layouts and a mix of Halo and Spark containers. I'm not sure what layout you're trying to create.
That said, take a look at the swapChildren method. Something like this should work:
this.swapChildren(refresh2, searchMsgList);
But it will most likely hide your refresh button, which seems less than ideal.
A few things strike me:
Inside your first VGroup you have x and y values specified. I thought those values were ignored inide VGroups, which automatically position your children in a vertical line.
I see an closing </mx:Canvas> tag, but not an opening canvas tag. It is unusual to me to use a canvas among all the HGroups and VGroups.