Finally, I found the solution. My editor was inherited from qtextedit. I add this lines to each action, and it works now!
void MyEditor::addActionToToolbar(QAction *a)
{
a->setShortcutContext(Qt::WidgetWithChildrenShortcut);
addAction(a);
QToolButton* btn = new QToolButton(this);
btn->setDefaultAction( a );
btn->setFocusPolicy(Qt::NoFocus);
btn->setSizePolicy( QSizePolicy::Fixed, QSizePolicy::Fixed );
btn->setIconSize(QSize(16,16));
toolBar->addWidget(btn);
}