Safe Key Presses

[Visitor Q]

It seems like every time I think I have it all figured out, there is another bend in the road.

Is there a general rule of thumb for safe keys to use when configuring a control panel?

I though I had it all covered but I have since run into two issues with the following emus.

SSF (Saturn Emulator) - Problem - Num Lock Keys can not be used for control commands.

Visual Pinball - Problem - Key Press 4 cannot be reconfigured from coin insert

So my lesson so far is this, don't use num lock keys or number keys.

It would assume that function keys would be a bad choice as well as well as common used letters like “p” for pause.

Is there a general rule of thumb here? What works and what doesn’t? It would be cool to start some sorta data base for something like this…