MenuBar disappears only in IExplore

Hello,

I have a SWF application running, and somehow the MenuBar from my page disappears only in IExplore. At Chrome and Firefox this not occurs.

My MXML file looks like this:

<mx:MenuBar id="mnePrincipal" labelField="@label"

                 styleName="mainMenu" menuStyleName="subMenu"  

                 itemClick="menuHandler(event);"

                 borderColor="0xFF0000"

                 rollOverColor="0xFF0000"

                 y="2"

                 alpha="0.0" fontSize="10"

                 fontWeight="bold" focusAlpha="0.3">

                     <mx:XMLList>

                        <menuitem label="MenuItem A">

                            <menuitem label="SubMenuItem A-1" enabled="false"/>

                            <menuitem label="SubMenuItem A-2"/>

                        </menuitem>

                        <menuitem label="MenuItem B"/>

                    </mx:XMLList>

                 </mx:MenuBar>

Any tips?