I don't actually get your problem here. Why would you want to right-click on the sample waveform and then press A (or the other way around), if not for speeding up sample editing? If you right-click, the context menu opens, and if there's an entry, where the key you're pressing is underlined, then this command is executed.

it happens all the time when playing back samples, especially trying to set loop points. the A key is C so of course it's going to be one of the default ones i use for playing back samples, and the slightest overlap between playing a sample with A and right clicking to set a loop point or even jsut right clicking accidentally slices the sample. also there's nothing underlined so idk what youre getting at with that

It is intentional that "A" is an accelerator key in the context menu, but it is of course not intentional that it makes a destructive action very easy to reach. I might just remove the accelerator altogether.

Side note on your last sentence: On "modern" Windows (since 7 or Vista?) accelerator keys are not underlined by default when the mouse is used to open a menu. In the control panel you can still tell Windows to always underline accelerator keys, which is what I personally prefer.

I removed the accelerator key in r10994.