Force same WM_CLASS as the Qt4 UI

modules/video_output/xcb/window.c

@@ -147,7 +147,7 @@ static int Open (vlc_object_t *obj)
     set_ascii_prop (conn, window, XA_WM_ICON_NAME,
                     pgettext ("ASCII VLC", "VLC"));
     xcb_change_property (conn, XCB_PROP_MODE_REPLACE, window, XA_WM_CLASS,
-                         XA_STRING, 8, 8, "vlc\0VLC");
+                         XA_STRING, 8, 8, "vlc\0Vlc");
     set_hostname_prop (conn, window);
 
     wnd->handle.xid = window;