if I use the file upload component inside a modalPannel and set the parameter allowFlash="true" the "add" button of the file upload doesnt open the file dialog window. Maybe a bug?

my code :

<rich:modalPanel id="panel" width="500" height="500">
 <f:facet name="header">
 <h:panelGroup>
 <h:outputText value="Modal Panel"></h:outputText>
 </h:panelGroup>
 </f:facet>
 <f:facet name="controls">
 <h:panelGroup>
 <h:outputText value="close" style="cursor:pointer" id="hidelink"/>
 <rich:componentControl for="panel" attachTo="hidelink" operation="hide" event="onclick"/>
 </h:panelGroup>
 </f:facet>

 <a4j:form>
 <rich:fileUpload fileUploadListener="#{FileUpload.uploadListener}"
 maxFilesQuantity="5" reRender="upload" id="upload" immediateUpload="false"
 acceptedTypes="jpg, gif, png, bmp" allowFlash="true">
 <a4j:support event="onuploadcomplete" reRender="info" />
 </rich:fileUpload>
 </a4j:form>

 </rich:modalPanel>