protected boolean matchesResultNode(DBNNode node) {
        if (node instanceof DBSWrapper) {
            DBSObject object = ((DBSWrapper) node).getObject();
            if (object != null && matchesType(object, true)) {
                return true;
            }
            object = DBUtils.getAdapter(DBSObject.class, object);
            return object != null && matchesType(object, true);
        } else if (node instanceof DBNObjectNode) {
            return matchesType(((DBNObjectNode) node).getNodeObject(), true);
        } else {
            return matchesType(node, true);
        }
    }
Expands first level of each node
plugins/org.jkiss.dbeaver.ui.navigator/src/org/jkiss/dbeaver/ui/navigator/dialogs/ObjectBrowserDialogBase.java