GdkKeymap default for Display problem

[Richard Shann <richard rshann plus com>]

Using Gtk 3.22.11 under Debian stable I get a different keymap than the
one the application was launched with on calling 

gdk_keymap_get_for_display(gdk_display_get_default ())

This shows up when there are two keymaps available and I select the
alternative one for a terminal, launch the application and then use 

gdk_keymap_translate_keyboard_state ()

what happens is that it is *not* translated using the keymap that was
used to launch the application (and which shows up in GtkEntry etc
widgets). Instead it is translated using the "default" keymap for the
Desktop.
This lead me to look at the documentation and I see that there is
nothing to suggest you can access the GdkKeymap that the GtkWidgets are
using - indeed there is nothing to suggest you can create a GdkKeymap
other than getting this "default for display" keymap.

Is there something I've missed here?

Richard Shann