Using master (98958c81f5065a5de13699d46995d278ecb6709e) with Qt `5.12.3` (also tested with depends) with multiple wallets available. None are shown in the `Open Wallet ->` menu in the gui. The wallets can be loaded from the console, bitcoin-cli etc.
#ifdef Q_OS_MAC
#include <qt/macdockiconhandler.h>
#endif
#include <chain.h>
#include <chainparams.h>
#include <interfaces/handler.h>
#include <interfaces/node.h>
#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>