@Override Widget computeTabGroup() { ToolItem[] items = _getItems(); if (tabItemList == null) { int i = 0; while (i < items.length && items[i].control == null) i++; if (i == items.length) return super.computeTabGroup(); } int index = indexOf(currentFocusItem); if (index == -1) index = items.length - 1; while (index >= 0) { ToolItem item = items[index]; if (item.isTabGroup()) return item; index--; } return super.computeTabGroup(); }