UI: Fix flash when starting minimized

Rather than showing the main window, then hiding it again when the
tray icon initialization happens, just don't show the main window.

When deciding whether to show the window, we need to know whether
the tray icon is available or not - if it's not and we don't show
the window, there would be no way to restore OBS.

UI/window-basic-main.cpp

@@ -1885,9 +1885,21 @@ void OBSBasic::OBSInit()
 
 	connect(ui->preview, &OBSQTDisplay::DisplayCreated, addDisplay);
 
+	/* Show the main window, unless the tray icon isn't available
+	 * or neither the setting nor flag for starting minimized is set. */
+	bool sysTrayEnabled = config_get_bool(App()->GlobalConfig(),
+					      "BasicWindow", "sysTrayEnabled");
+	bool sysTrayWhenStarted = config_get_bool(
+		App()->GlobalConfig(), "BasicWindow", "SysTrayWhenStarted");
+	bool hideWindowOnStart = QSystemTrayIcon::isSystemTrayAvailable() &&
+				 sysTrayEnabled &&
+				 (opt_minimize_tray || sysTrayWhenStarted);
+
 #ifdef _WIN32
 	SetWin32DropStyle(this);
-	show();
+
+	if (!hideWindowOnStart)
+		show();
 #endif
 
 	bool alwaysOnTop = config_get_bool(App()->GlobalConfig(), "BasicWindow",
@@ -1911,7 +1923,8 @@ void OBSBasic::OBSInit()
 	}
 
 #ifndef _WIN32
-	show();
+	if (!hideWindowOnStart)
+		show();
 #endif
 
 	/* setup stats dock */
@@ -9064,9 +9077,7 @@ void OBSBasic::SystemTray(bool firstStarted)
 	} else {
 		trayIcon->show();
 		if (firstStarted && (sysTrayWhenStarted || opt_minimize_tray)) {
-			QTimer::singleShot(50, this, SLOT(hide()));
 			EnablePreviewDisplay(false);
-			setVisible(false);
 #ifdef __APPLE__
 			EnableOSXDockIcon(false);
 #endif