Problem with setShowGroupSummaryInHeader(true) and recordComponent

Hi,

I've found some problems to show buttons in grid group header...

If setShowGroupSummaryInHeader() is set to FALSE, my grid display
action field with ImageButton in group summary correctly, but if I set it to TRUE, recordComponent disappear and I don't see ImageButton

I know that my english is not well so this is my sample code:

piattiGrid = new ListGrid(){
@Override
protected Canvas createRecordComponent(final ListGridRecord record, Integer colNum) {

if (this.getFieldName(colNum).toLowerCase().equals("action")) {

//if(record.getIsGroupSummary()){
HLayout recordCanvas = new HLayout(10);
recordCanvas.setHeight(35);
recordCanvas.setAlign(Alignment.CENTER);
recordCanvas.setAlign(VerticalAlignment.CENTER);


ImgButton delImg = new ImgButton();
delImg.setShowDown(false);
delImg.setShowRollOver(false);
delImg.setSrc(GWT.getHostPageBaseURL() + "images/delete.png");

delImg.setPrompt("Elimina");
delImg.setHeight(25);
delImg.setWidth(25);


recordCanvas.addMember(attivaImg);
recordCanvas.addMember(editImg);
recordCanvas.addMember(delImg);

return recordCanvas;

}
return null;
}
};
piattiGrid.setShowRecordComponents(true);
piattiGrid.setShowRecordComponentsByCell(true);
piattiGrid.setWidth(Helper.getScreenWidth() - 360);
piattiGrid.setHeight(Helper.getContentHeight() - 50);
piattiGrid.setDataSource(ConfigurazionePiattiDS.getInstance());
piattiGrid.setFastCellUpdates(true);
piattiGrid.setDataFetchMode(FetchMode.BASIC);
piattiGrid.setAutoFetchData(false);
piattiGrid.setSortField("nome");
piattiGrid.setSortDirection(SortDirection.ASCENDING);
piattiGrid.setUseAllDataSourceFields(false);
piattiGrid.setWrapCells(true);
piattiGrid.setGroupByField("nome");
piattiGrid.setShowGroupSummary(true);
piattiGrid.setShowGroupSummaryInHeader(true);
piattiGrid.setGroupStartOpen(GroupStartOpen.ALL);

ResultSet rsProperties = new ResultSet();
rsProperties.setUseClientSorting(false);
rsProperties.setUseClientFiltering(false);

piattiGrid.setDataProperties(rsProperties);

ListGridField nomeField = new ListGridField("nome", "Nome");
nomeField.setWidth("100%");
nomeField.setCanFilter(false);
nomeField.setShowGroupSummary(true);
nomeField.setShowGridSummary(false);


ListGridField actionField = new ListGridField("action", "Azioni");
actionField.setCanFilter(false);
actionField.setAlign(Alignment.CENTER);
actionField.setWidth(150);
actionField.setCanEdit(false);
actionField.setShowGroupSummary(true);
actionField.setShowGridSummary(false);


piattiGrid.setFields(nomeField, actionField);



I've smartgwt 4.1p and I've found this problem during development on eclipse, so I've tested this code only in firefox 24.5.0

Thx for any help...