Fixed stuck window activity after a quick hide and show on X11.

Messages in an opened chat were not marked as read after the window
was shown back from the tray.

Telegram/SourceFiles/platform/linux/main_window_linux.cpp

@@ -522,6 +522,9 @@ bool MainWindow::eventFilter(QObject *obj, QEvent *evt) {
 		}
 	} else if (obj == this && t == QEvent::Hide) {
 		_exposed = false;
+		if (IsX11()) {
+			destroy();
+		}
 	} else if (obj == this && t == QEvent::ThemeChange) {
 		updateWindowIcon();
 	}