<!-- 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. 

#include <ui_interface.h>
#include <util/system.h>
#include <iostream>
#include <memory>
#include <QAction>
#include <QApplication>
#include <QComboBox>
#include <QDateTime>
#include <QDesktopWidget>
#include <QDragEnterEvent>
#include <QListWidget>
#include <QMenu>
#include <QMenuBar>
#include <QMessageBox>
#include <QMimeData>
#include <QProgressDialog>
#include <QSettings>
#include <QShortcut>
#include <QStackedWidget>
#include <QStatusBar>
#include <QStyle>
#include <QSystemTrayIcon>
#include <QTimer>
#include <QToolBar>
#include <QUrlQuery>
#include <QVBoxLayout>
#include <QWindow>
const std::string BitcoinGUI::DEFAULT_UIPLATFORM =
#if defined(Q_OS_MAC)
        "macosx"