Typing in editable combobox with many entries is very slow when completer is used

In the following example, each keystroke in the lineedit takes about 600ms before the UI reacts. Using QCompleter::PopupCompletion is much faster, as there are viewer items that the view has to layout.

#include <QtGui>

int main(int argc, char **argv)
{
QApplication app(argc, argv);

QStringList items;
for (int i = 1; i < 9999; ++i)
items << QString("%1").arg;

QWidget widget;
QComboBox combo;
combo.setEditable(true);
combo.setInsertPolicy(QComboBox::NoInsert);
combo.completer()->setCompletionMode(QCompleter::UnfilteredPopupCompletion);
combo.addItems(items);

QHBoxLayout* hbox= new QHBoxLayout(&widget);
hbox->addWidget(&combo);

widget.show();
return app.exec();
}