ListGrid: valueIcons for empty cells

[pavel.benes]

Hello Isomorphic,

I have a question regarding Value icons in listgrid field.
When a field 'bool 'of type BOOLEAN has value icons defined as such:

valueIcons.put("true", "IconBooleanTrue");
valueIcons.put("false", "IconBooleanFalse");
valueIcons.put("null", "IconBooleanNull");

and the grid has records with the field 'bool' being populated with "true"/"false" or left empty, the value icons do not show for the empty cells.
Now I do realise, that there is no actual "null" within these cells, so it would make sense that no value icon is displayed for empty cells but when I try to retrieve the corresponding valueIcon from a record's field via ListGrid.getValueIcon(ListGridField, Object, ListGridRecord) it does recognise that for an empty cell, the value icon should be "KiIconBooleanNull" (but doesn't display it).

I suppose this could be achieved by overriding ListGrid.getValueIcon() as specified in the docs but I just find it curious, that the value icon is determined to a valid value but not displayed.

SmartGWT: v12.0p_2018-08-25/Pro Deployment (built 2018-08-25)
Chrome 68.0.3440.106
Test case for completeness sake:

 @Override
public void onModuleLoad() {
        ListGrid grid = new ListGrid();
        grid.setWidth(800);
        grid.setHeight(600);
        grid.addRecordClickHandler(new RecordClickHandler() {
            @Override
            public void onRecordClick(RecordClickEvent event) {
                String fieldN = event.getField().getName();
                GWT.log("record value: " + event.getRecord().getAttribute(fieldN));
                GWT.log(grid.getValueIcon(event.getField(), event.getRecord().getAttribute(fieldN), event.getRecord()));              }
        });

        ListGridField lgf = new ListGridField("bool", 150);
        lgf.setType(ListGridFieldType.BOOLEAN);
        Map<String, String> valueIcons = new HashMap<String, String>();
        valueIcons.put("true", "IconBooleanTrue");
        valueIcons.put("false", "IconBooleanFalse");
        valueIcons.put("null", "IconBooleanNull");
        lgf.setValueIcons(valueIcons);
        lgf.setImageURLSuffix(".svg");

        ListGridField lgfID = new ListGridField("id", 50);
        lgfID.setType(ListGridFieldType.INTEGER);

        grid.setFields(lgfID, lgf);

        ListGridRecord r1 = new ListGridRecord();
        r1.setAttribute("bool", true);
        r1.setAttribute("id", 1);
        ListGridRecord r2 = new ListGridRecord();
        r2.setAttribute("bool", false);
        r2.setAttribute("id", 2);
        ListGridRecord r3 = new ListGridRecord();
        r3.setAttribute("id", 3);
        grid.setData(r1, r2, r3);
        grid.draw();
}

[Isomorphic]

Put an actual null into the record rather than leaving the value undefined.