BTW, keep in mind that there is no such thing as "universal ref" in C++ standard. It's just a way of thinking about rvalue ref T&& in contexts which provide type deduction for T

since I hate sender() and pb->children().at(0) is even less robust I suggest (assuming you declared QMenu* MainWindow::m): connect(sel, &QPushButton::released, [=]()->void{ const QSize size = m->sizeHint(); m->popup(sel->mapToGlobal(QPoint(0,-size.height()))); }); P.S. Looking at this functionality, are you sure QToolButton is not a better choice? see QToolButton::setMenu

@VRonin said in Template: Force const parameter: why wouldn't a simple static_assert work here? It definitely would.

You're welcome ! SInce everything is OK now, please update the thread title prepending [solved] so other forum users may know a solution has been found :) Also, while browsing the forum, consider up-voting the answers that helped you, it will make them easier to find for other users :)

Hi @clogwog Use Screen to get the Screen's deimesions. Bind the width and height of root element to it.

Qt developers have investigated this before, and there is a partially-working patch. There are still a number of important challenges to work through, but devs are focussing on other things at the moment. It is not currently being actively worked on: http://comments.gmane.org/gmane.comp.lib.qt.devel/10327

Hi and welcome to devnet, That might interest you

Thanks for your answers! I think I will go with Template specialization. CU mts