c++ - Requires 2 right clicks to switch context menus among items? -

code below

#include <qtwidgets> #include <qglwidget>  int main(int argc, char *argv[]) {     qapplication a(argc, argv);     qmainwindow w;      w.setcentralwidget(new qglwidget(&w)); // w.setcentralwidget(new qwidget(&w));      qtreewidget* tree = new qtreewidget(&w);     qtreewidgetitem* item0 = new qtreewidgetitem(tree, qstringlist("a"));     qtreewidgetitem* item1 = new qtreewidgetitem(tree, qstringlist("b"));     tree->setcontextmenupolicy(qt::customcontextmenu);     qobject::connect(tree, &qtreeview::customcontextmenurequested, [](){         qmenu menu;         menu.addaction("a");         menu.exec(qcursor::pos());     });      qdockwidget* dock = new qdockwidget("tree", &w);     dock->setwidget(tree);     w.adddockwidget(qt::leftdockwidgetarea, dock);      w.show();     return a.exec(); } 

compile , run it. requires 2 right clicks switch context menus among items. however, if change qglwidget qwidget. fine. 1 right click can switch context menus among items. bugs??? lot.

some observations:

• switch positions of tree , gl widget ok, i.e. set tree central widget , gl widget 1 in dock.

it seems right click event goes central widget , blocked gl widget.