Bug 72615 [Viewers] Need and ITableFontProvider
We released an ITabelColorProvider for M2 - we should have a corresponding ITableFontProvider
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
public void add(Object parentElement, Object[] childElements) {
        Assert.isNotNull(parentElement);
        assertElementsNotNull(childElements);
        Widget widget = findItem(parentElement);
        
        if (widget == null)
            return;
        Control tree = getControl();
        
        
        if (widget instanceof Item) {
            Item ti = (Item) widget;
            if (!getExpanded(ti)) {
                boolean needDummy = isExpandable(parentElement);
                boolean haveDummy = false;
                
                Item[] items = getItems(ti);
                for (int i = 0; i < items.length; i++) {
                    if (items[i].getData() != null) {
                        disassociate(items[i]);
                        items[i].dispose();
                    } else {
                        if (needDummy && !haveDummy) {
                            haveDummy = true;
                        } else {
                            items[i].dispose();
                        }
                    }
                }