kozura

%YOUR_QT%/plugins/imageformats

plugins: qjpg.dll, qpng.dll ... qsomething.dll ^^) ..

profit

Переопределите виртуальные методы для QComboBox:

QComboBox::showPopup()
QComboBox::hidePopup()

Вот так:

QTreeWidgetItem* top_level = new QTreeWidgetItem(m_three);

QTreeWidgetItem* child_item = new QTreeWidgetItem(top_level);

Либо:

QStandardItemModel model(rows, columns);

QStandardItem *item = new QStandardItem("top");
QStandardItem *child = new QStandardItem("child");

model.setItem(row, column, item);