Issues with ZERO on SetVariable Controls

I have this ongoing problem with SetVariable controls in panels. Perhaps I am missing an easy answer or one that has already been posted.

I have SetVariable controls that are designed to step between -N to N in increments. The increments should go identically through 0 (zero). Invariably, as I step through the values, the ZERO becomes something akin to 2.7 x 10^(-17) rather than EXACTLY ZERO.

What am I missing here?

OK. I would think that a range -2 to 2 with increments 0.1 would not have this problem. Here is the setvariable control extracted from the panel. The value _should_ be exactly zero. It increments up/down to exact values above/below 0.1 or -0.1 with no issues.

SetVariable setvarA,fSize=14,limits={-2,2,0.1},value= _NUM:2.77555756156289e-17

Here is the value with a format code in the panel display. The value shows 0.0 but is not set at zero exactly.

SetVariable setvarA,fSize=14,format="%3.1f"
SetVariable setvarA,limits={-2,2,0.1},value= _NUM:2.77555756156289e-17

Here is the statement with an increment at 0.1.

SetVariable setvarA,fSize=14,format="%3.1f",limits={-2,2,0.1},value= _NUM:0.1

When I update to 0 manually, the value is _NUM:0 (exactly).

The precision offset is not critical in my calculations. But it could be for someone. Should there be a standard way to avoid this? Something akin to a checkbox: [  ] round number values to format precision.

Igor Pro 7.08 on macOS 10.13.6

Well! I learned something that I probably did know vaguely but never really had hit home properly.

I have a feature request in the works.