JBoss/RichFaces: Action not called if first selectOneMenu in DataTable is empty - jboss

Question

I have a problem with richfaces page on JBoss. The page contains (among other things) a list of projects that are to be closed. Before the project can be closed a reason has to be selected. Not all projects need to be filled out. The ones that are left blank are not closed and remain in the table.
Now the problem: If the first row is left blank (no matter which other rows are filled out), the page reloads but the function specified as action on the command button (adminInformationBean.startClosingProjects()) is never called. If a reason is selected at least for the first row, everything is working fine.
This is the xhtml file:
<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:s="http://jboss.org/schema/seam/taglib"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:rich="http://richfaces.org/rich"
template="/layout/template.xhtml"
xmlns:a4j="http://richfaces.org/a4j">
<ui:define name="body">
<div id="cku1405090004">
<h:form id="uma1407080001">
<div>
<rich:panel styleClass="PanelHeader">
<f:facet name="header">
#{messages.adminInfo_table_header}
</f:facet>
<rich:tabPanel id="myTabPanelAdminInfo" styleClass="PanelHeader">
[...]
<!-- closed Projects -->
<rich:tab id="closedProjects">
<f:facet name="header">#{messages.adminInfo_table_type_close}
<h:outputText value="#{adminInformationBean.closedProjectsSize}"/>
</f:facet>
<div class="actionButtons">
<div class="ViewButtonLeft" />
<h:commandButton id="cku1405090011" styleClass="ViewSubmitButtonBody" value="#{messages['adminInfo_table_button_check']}" action="#{adminInformationBean.startClosingProjects()}" onclick="doPostBack();"/>
<div class="ViewButtonRight" />
</div>
<rich:dataTable id="closedProjectsTableId" styleClass="rich-datatable" value="#{adminInformationBean.infoListClosedProjects}" var="adminInfo" iterationStatusVar="iterator" rows="#{adminInformationBean.selectedItem}" rowKeyVar="row" rowClasses="ViewOddLine, ViewEvenLine">
<f:facet name="noData">#{messages.team_table_filter_message}</f:facet>
<f:facet name="header">
<rich:columnGroup>
<rich:column>
<span>
<h:outputText value="#{messages.adminInfo_table_header_projectName} " />
</span>
</rich:column>
<rich:column>
<span>
<h:outputText value="#{messages.adminInfo_table_header_reason}" />
</span>
</rich:column>
</rich:columnGroup>
</f:facet>
<rich:column filterValue="#{filterBean.projectNameFilter}" filterExpression="#{fn:containsIgnoreCase(adminInfo.projectName, filterBean.projectNameFilter)}">
<f:facet name="header">
<h:panelGroup>
<h:inputText id="projectNameClose" value="#{filterBean.projectNameFilter}">
<a4j:ajax render="closedProjectsTableId#body, tgrid2Id4#body" execute="#this" event="keyup" />
</h:inputText>
</h:panelGroup>
</f:facet>
<span>
<h:outputText value="#{adminInfo.projectName}" rendered="#{adminInfo.projectName != null}"/>
</span>
</rich:column>
<rich:column>
<div align="center">
<h:selectOneMenu class="selectReason" value="#{adminInfo.reason}">
<s:selectItems value="#{adminInformationBean.possibleReasons}" var="reason" label="#{reason.name}" itemValue="#{reason.id}" noSelectionLabel="" />
</h:selectOneMenu>
</div>
</rich:column>
</rich:dataTable>
<h:panelGrid id="tgrid2Id4" columns="3">
#{messages.team_table_rows_selectonemenu}
<h:selectOneMenu value="#{adminInformationBean.selectedItem}" onchange="submit()" valueChangeListener="#{adminInformationBean.pageSizeValueChanged}">
<f:selectItems value="#{adminInformationBean.selectItemsMap}"/>
</h:selectOneMenu>
<rich:dataScroller for="closedProjectsTableId" page="#{adminInformationBean.page}" maxPages="" fastControls="hide">
<f:facet name="first">
<h:outputText value="<<"/>
</f:facet>
<f:facet name="previous">
<h:outputText value="<"/>
</f:facet>
<f:facet name="next">
<h:outputText value=">"/>
</f:facet>
<f:facet name="last">
<h:outputText value=">>"/>
</f:facet>
</rich:dataScroller>
</h:panelGrid>
<div class="actionButtons" style="padding-bottom: 20px">
<div>
<div class="ViewButtonLeft" />
<h:commandButton id="cku1405090012" styleClass="ViewSubmitButtonBody" value="#{messages['adminInfo_table_button_check']}" action="#{adminInformationBean.startClosingProjects()}" onclick="doPostBack();"/>
<div class="ViewButtonRight" />
</div>
</div>
</rich:tab>
[...]
</rich:tabPanel>
</rich:panel>
</div>
</h:form>
</div>
</ui:define>
</ui:composition>