+void Header::contextMenuEvent(QContextMenuEvent *event)
+{
+ const shared_ptr<ViewItem> r = get_mouse_over_item(mouse_point_);
+ if (!r)
+ return;
+
+ QMenu *menu = r->create_context_menu(this);
+ if (!menu)
+ menu = new QMenu(this);
+
+ if (std::count_if(view_.begin(), view_.end(), item_selected) > 1)
+ {
+ menu->addSeparator();
+
+ QAction *const group = new QAction(tr("Group"), this);
+ QList<QKeySequence> shortcuts;
+ shortcuts.append(QKeySequence(Qt::ControlModifier | Qt::Key_G));
+ group->setShortcuts(shortcuts);
+ connect(group, SIGNAL(triggered()), this, SLOT(on_group()));
+ menu->addAction(group);
+ }
+
+ menu->exec(event->globalPos());
+}
+
+void Header::keyPressEvent(QKeyEvent *e)
+{
+ assert(e);
+
+ MarginWidget::keyPressEvent(e);
+
+ if (e->key() == Qt::Key_G && e->modifiers() == Qt::ControlModifier)
+ on_group();
+ else if (e->key() == Qt::Key_U && e->modifiers() == Qt::ControlModifier)
+ on_ungroup();
+}
+
+void Header::on_group()
+{
+ vector< shared_ptr<RowItem> > selected_items(
+ make_filter_iterator(item_selected, view_.begin(), view_.end()),
+ make_filter_iterator(item_selected, view_.end(), view_.end()));
+ stable_sort(selected_items.begin(), selected_items.end(),
+ [](const shared_ptr<RowItem> &a, const shared_ptr<RowItem> &b) {
+ return a->visual_v_offset() < b->visual_v_offset(); });
+
+ shared_ptr<TraceGroup> group(new TraceGroup());
+ shared_ptr<RowItem> mouse_down_item(
+ std::dynamic_pointer_cast<RowItem>(mouse_down_item_));
+ shared_ptr<RowItem> focus_item(
+ mouse_down_item ? mouse_down_item : selected_items.front());
+
+ assert(focus_item);
+ assert(focus_item->owner());
+ focus_item->owner()->add_child_item(group);
+
+ // Set the group v_offset here before reparenting
+ group->force_to_v_offset(focus_item->layout_v_offset() +
+ focus_item->v_extents().first);
+
+ for (size_t i = 0; i < selected_items.size(); i++) {
+ const shared_ptr<RowItem> &r = selected_items[i];
+ assert(r->owner());
+ r->owner()->remove_child_item(r);
+ group->add_child_item(r);
+
+ // Put the items at 1-pixel offsets, so that restack will
+ // stack them in the right order
+ r->set_layout_v_offset(i);
+ }
+}
+
+void Header::on_ungroup()
+{
+ bool restart;
+ do {
+ restart = false;
+ for (const shared_ptr<RowItem> r : view_) {
+ const shared_ptr<TraceGroup> tg =
+ dynamic_pointer_cast<TraceGroup>(r);
+ if (tg && tg->selected()) {
+ tg->ungroup();
+ restart = true;
+ break;
+ }
+ }
+ } while (restart);
+}
+