Code:
<object id="mainWindow" class="mx.containers.Panel">
</object>
it works fine.

which one of following is correct?
Code:
<object id="mainWindow" class="mx.containers.Panel">
<property name="title" value="hello world" />
</object>
Code:
<object id="mainWindow" class="mx.containers.Panel">
<param name="title" value="hello world" />
</object>
thanks