Your right it also works for me. When I was initially testing, the menuBar component was inside a dataTable component. Here is some sample code:
<ice:dataTable id="dataTable"
var="user"
value="#
{testBean.userList}
">
<ice:column>
<f:facet name="header">
<ice:outputText value="Menu Section"/>
</f:facet>
<ice:menuBar id="menu" displayOnClick="true">
<ice:menuItem value="Menu Items">
<ice:menuItem value="Menu Item 1"/>
<ice:menuItem value="Menu Item 2"/>
</ice:menuItem>
</ice:menuBar>
</ice:column>
<ice:column>
<f:facet name="header">
<ice:outputText value="Name"/>
</f:facet>
<ice:outputText value="#
{user.name}
"/>
</ice:column>
<ice:column>
<f:facet name="header">
<ice:outputText value="Password"/>
</f:facet>
<ice:outputText value="#
{user.password}
"/>
</ice:column>
<ice:column>
<f:facet name="header">
<ice:outputText value="Address"/>
</f:facet>
<ice:outputText value="#
{user.address}
"/>
</ice:column>
</ice:dataTable>
I also used the first code snippet outside of the dataTable and it displayed similar issue as reported. Without the dataTable on the page it is displayed correctly.
I have tested the above menu snippet with the head, and didn't see any problem with any of the browser.