I just put side by side the newest version of lxkeymap and the lxkb-config and I didn't see any new things... And lxkeymap have a place "Type here to test your keyboard". Maybe I'm missing something??
If you don't want to let your software to be outdated, you soon will need to port it to gtk3.
By the way, I think the correct word at the bottom would be "accept", and not "acept".