Merge bitcoin#14594: qt: Fix minimized window bug on Linux

a88640e Fix minimized window bug on Linux (Hennadii Stepanov)

Pull request description:

  Fix bitcoin#14591

  On some Linux systems the minimized to the taskbar (iconified) main window cannot be restored properly using actions from the systray icon menu when `QSystemTrayIcon::contextMenu()` is a child of the main window.

Tree-SHA512: 05c9f724fc2278d45dac6fe72b09859f12b5d71f54659bb779403c8cd81b55e610fb7b5aa912ac273d3cd19bf953b0405bbc6451feb00d1827c95dd9f0876aa4

src/qt/bitcoingui.cpp

@@ -36,6 +36,7 @@
 #include <qt/masternodelist.h>
 
 #include <iostream>
+#include <memory>
 
 #include <QAction>
 #include <QApplication>
@@ -45,6 +46,7 @@
 #include <QDesktopWidget>
 #include <QDragEnterEvent>
 #include <QListWidget>
+#include <QMenu>
 #include <QMenuBar>
 #include <QMessageBox>
 #include <QMimeData>
@@ -54,6 +56,7 @@
 #include <QStackedWidget>
 #include <QStatusBar>
 #include <QStyle>
+#include <QSystemTrayIcon>
 #include <QTimer>
 #include <QToolBar>
 #include <QToolButton>
@@ -73,8 +76,9 @@ const std::string BitcoinGUI::DEFAULT_UIPLATFORM =
 
 BitcoinGUI::BitcoinGUI(interfaces::Node& node, const NetworkStyle* networkStyle, QWidget* parent) :
     QMainWindow(parent),
-    m_node(node)
-{
+    m_node(node),
+    trayIconMenu{new QMenu()},
+
     GUIUtil::loadTheme(true);
 
     QSettings settings;

src/qt/bitcoingui.h

@@ -14,7 +14,6 @@
 #include <QLabel>
 #include <QMainWindow>
 #include <QMap>
-#include <QMenu>
 #include <QPoint>
 #include <QPushButton>
 #include <QSystemTrayIcon>
@@ -46,6 +45,7 @@ QT_BEGIN_NAMESPACE
 class QAction;
 class QButtonGroup;
 class QComboBox;
+class QMenu;
 class QProgressBar;
 class QProgressDialog;
 class QToolButton;
@@ -152,7 +152,7 @@ class BitcoinGUI : public QMainWindow
     QComboBox* m_wallet_selector = nullptr;
 
     QSystemTrayIcon* trayIcon = nullptr;
-    QMenu* trayIconMenu = nullptr;
+    const std::unique_ptr<QMenu> trayIconMenu;
     QMenu* dockIconMenu = nullptr;
     Notificator* notificator = nullptr;
     RPCConsole* rpcConsole = nullptr;