It's well documented bug in richfaces (see bug RF-11413)
You can try it on Richfaces showcase rich:dataTable -> editing
Only solution I find is : https://community.jboss.org/message/735198 (look for answer from Eldin Okanovic)
But it doesn't work for me, so i came up with similar solution, that works for me.
In xhtml rich:datatable add action on a4j:commandLink action="#{carsBean.popupReset}"
<a4j:commandLink styleClass="no-decor" render="editGrid" execute="@this"
oncomplete="#{rich:component('editPane')}.show()" action="#{carsBean.popupReset}">
<h:graphicImage value="/images/icons/edit.gif" alt="edit" />
<a4j:param value="#{it.index}" assignTo="#{carsBean.currentCarIndex}"/>
<f:setPropertyActionListener target="#{carsBean.editedCar}" value="{car}" />
</a4j:commandLink>
In CarsBean add method carsBean.popupReset
public void popupReset() {
FacesContext context = FacesContext.getCurrentInstance();
UIInput com1 = (UIInput) context.getViewRoot().findComponent("form:price");
UIInput com2 = (UIInput) context.getViewRoot().findComponent("form:mage");
...
com1.resetValue();
com1.setValue(editedCar.getPrice());
com2.resetValue();
com2.setValue(editedCar.getMileage());
...
}
It's not pretty solution but so far it works for me.