Second try:
added Qt::CTRL + Qt::Key_T and Qt::CTRL + Qt::SHIFT + Qt::Key_N
as QKeySequence::AddTab is only Qt::CTRL + Qt::SHIFT + Qt::Key_N
under plasma.
QAction* newTab = actionCollection()->addAction(QStringLiteral("new_tab"));
newTab->setIcon(QIcon::fromTheme(QStringLiteral("tab-new")));
newTab->setText(i18nc("@action:inmenu File", "New Tab"));
- actionCollection()->setDefaultShortcuts(newTab, {QKeySequence::AddTab});
+ actionCollection()->setDefaultShortcuts(newTab, {Qt::CTRL + Qt::Key_T, Qt::CTRL + Qt::SHIFT + Qt::Key_N});
connect(newTab, &QAction::triggered, this, static_cast<void(DolphinMainWindow::*)()>(&DolphinMainWindow::openNewActivatedTab));
QAction* closeTab = KStandardAction::close(