<!-- Describe the issue -->
Hello evryone, I get nothing when I click in open wallet, I am new to bitcoin and expect to show something.

![BitcoinIssue](https://user-images.githubusercontent.com/39341595/57179721-5024fc00-6e9e-11e9-80dd-af5e4345be48.png)

I'am using Bitcoin Core (both in testnet and mainnet, didn't work) 0.18 on window 10. 

{
    onDisplayUnitsClicked(event->pos());
}
void UnitDisplayStatusBarControl::createContextMenu()
{
    menu = new QMenu(this);
    for (const BitcoinUnits::Unit u : BitcoinUnits::availableUnits())
    {
        QAction *menuAction = new QAction(QString(BitcoinUnits::longName(u)), this);
        menuAction->setData(QVariant(u));
        menu->addAction(menuAction);
    }
    connect(menu, &QMenu::triggered, this, &UnitDisplayStatusBarControl::onMenuSelection);
}
void UnitDisplayStatusBarControl::setOptionsModel(OptionsModel *_optionsModel)