Partially revert 30f21259f8.

Fixes Linux issue for when the theme doesn't have a corresponding icon.

src/gui/mainwindow.cpp

@@ -1512,11 +1512,6 @@ void MainWindow::checkForActiveTorrents()
 
 QIcon MainWindow::getSystrayIcon() const
 {
-#if (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
-    if (Preferences::instance()->useSystemIconTheme())
-        return QIcon::fromTheme("qbittorrent");
-#endif
-
     TrayIcon::Style style = Preferences::instance()->trayIconStyle();
     switch(style) {
     case TrayIcon::MONO_DARK:
@@ -1528,9 +1523,16 @@ QIcon MainWindow::getSystrayIcon() const
     }
 
     QIcon icon;
-    icon.addFile(":/icons/skin/qbittorrent16.png");
-    icon.addFile(":/icons/skin/qbittorrent22.png");
-    icon.addFile(":/icons/skin/qbittorrent32.png");
+#if (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
+    if (Preferences::instance()->useSystemIconTheme())
+        icon = QIcon::fromTheme("qbittorrent");
+
+#endif
+    if (icon.isNull()) {
+        icon.addFile(":/icons/skin/qbittorrent22.png", QSize(22, 22));
+        icon.addFile(":/icons/skin/qbittorrent16.png", QSize(16, 16));
+        icon.addFile(":/icons/skin/qbittorrent32.png", QSize(32, 32));
+    }
     return icon;
 }