Weird meld issue when merging large files. Help diagnose?

[Gilboa Davara <gilboad gmail com>]

Hello all,

When trying to compare large SVN based files via meld 3.16.2 (Fedora
RPM), I can no longer reliably Ctrl-D / E / Alt-Up / Down to the next
/ previous change and I the console is flooded by
"Gtk-WARNING **: Allocating size to GtkVBox 0x55ac29fc23c0 without
calling gtk_widget_get_preferred_width/height(). How does the code
know the size to allocate?" error messages.

Any idea how I can diagnose it?

- Gilboa