What will happen when the X server doesn't support XKB(XKEYBOARD)

[Adam Q]

There is a X server for win32 which doesn't support XKB extension(I
know it's unbelievable).

There is something strange when I try to use the
gnome-keyboard-properties and system-config-keyboard to change the X
server's keyboard layout.

When using gnome-keyboard-properties,the input of keyboard goes crazy
and can't be used.
When using system-config-keyboard the CLI just prints something like
"XKB extension unsupported" and nothing changed including the keyboard
layout.

I tested serveral X server from the latest Xorg server in Arch and
some old Xorg server in RHEL5.6/5.5 also with latest cygwin/X.
All the servers I tested above can change the keyboard using these 2 GUI.

I assume the problem is the lack of XKB extension but without XKB
extension,the client should just send a lot of ChangeKeyboardLayout
requests (and wireshark shows it really sends) to X server,and the
layout should change even without the XKB extension and no crazy
keyboard.

How can I determine where the problem really is?