ubuntu 24.04 meld error through ssh -X , but xclock works fine

meld through ssh -X from ubuntu mate 18.04 to 24.04 gets errors... apt search meld | grep meld outputs:

meld/noble,noble,now 3.22.2-1 all [installed]
python3-meld3/noble 1.0.2-4 amd64

apt search fuse | grep fuse | grep install:

fuse3/noble,now 3.14.0-5build1 amd64 [installed,automatic]
gvfs-fuse/noble,now 1.54.0-1ubuntu2 amd64 [installed,automatic]
libfuse3-3/noble,now 3.14.0-5build1 amd64 [installed,automatic]

Again, xlock displays just fine from 24.04 machine onto 18.04 But meld gets errors:

2025-06-05 12:46:12,494 CRITICAL Gtk: 
(org.gnome.Meld:8439): GLib-GIO-CRITICAL **: 12:46:12.494: GFileInfo created without standard::type
2025-06-05 12:46:12,494 CRITICAL Gtk: 
(org.gnome.Meld:8439): GLib-GIO-CRITICAL **: 12:46:12.494: file ../../../gio/gfileinfo.c: line 1610 (g_file_info_get_file_type): should not be reached
...

UPDATE1: I have a feeling that the error messages were a red herring: the result of the differences is actually shown on the monitor hooked up to the 24.04 machine. BTW, the error message have disappeared. xclock is still shown correctly in the X $DISPLAY localhost:11.0 So the problem now is: "meld" displays on the wrong monitor...