Unable to map Menu/Application key to a button input in SDLMAME

[netdoll]

MAME version

0.266

System information

Fedora Linux 40 x86_64, GK61 keyboard, SDLMAME as packaged by Fedora

INI configuration details

No response

Emulated system/software

No response

Incorrect behaviour

When using the input configuration for buttons (digital inputs in this case, but I think it extends to all button mappings in SDLMAME), attempting to map Menu/Application (X11 keycode 135) refuses to map and thus fails.

Expected behaviour

Menu/Application to map to any button input in the config menu (this case already works correctly on the official Windows version of MAME and on most third party emulators across platforms, SDL or not)

Steps to reproduce

1. Use SDLMAME as packaged by most Unix-like systems or build from source.
2. Open MAME and choose any game/device
3. Hit Tab, go into Input Settings -> Input Assignments (this system or global both work fine for the purposes of reproducing the behavior)
4. Attempt to map Menu/Application to any button (on Windows builds this should then show up as either Menu or Application and on SDLMAME it should refuse to be mapped if you press the key)

Additional details

No response