I think the calculator button is common to Microsoft keyboards. Mine is only a few years old, and a lot of what looks like dust is just matte texture I haven't worn through yet.

I'm aware there are workarounds. It's just strange to me that Spine is the only program blocking it.

There's a calculator key above the tenkey on my keyboard (pictured below). While I'm in any other program pressing this key brings up the Windows 10 Calculator, but while I'm in Spine no calculator comes up. So if I have any reason to calculate while animating I have to first tab over to a different program and then bring up the calculator there. Is this intended behavior?

As far as I know Spine has always performed this way, but if it's interrupting that input in some way as I suspect then I would like for it to stop.

If I select a group of keys and scale them with a negative scale then all of the keys keep their respective curves but this means that playback is different than if the original animation had been played in reverse, which is unexpected.

Example:
If key A has a linear interpolation to key B and B has a curve interpolation to key C, moving from A to B will have a linear blend but moving from B to A (if you scale it negatively) will have a curved blend.

The curves per key are preserved but the relationship between keys is not, and IMO the relationship between keys is far more important here. This also screws up the timing for any keys that utilizing a non-symmetrical interpolation curve, such as an ease-in or ease-out.

What I would expect to happen when negatively scaling a group of keys is for key N+1 to get the inverse curve of key N so that the relationships are preserved.