Difference in allowed accelerator keys between Qt and Wx

[drbsg]

There are a number of accelerator keys that the Wx backend allows that the Qt backend does not, for example symbols such as "-" and "=". Under Qt key_event_to_name maps them to 'Unknown-Key' because they are not explicitly listed in key_map, but under Wx there is a fall-back condition that passes through any key code accepted by chr.

Is this intended behaviour, perhaps enforcing a style guide, or an accident of history? 😄

This was spotted under traitsui v6.0.0, but it looks like the issue affects all versions since (and I haven't checked earlier).