Helical Sweep displays an Unselectable Temporary Axis

Hey folks, a coworker presented me with this and in nearly 23 years of using SolidWorks, I genuinely can't recall if I've ever encountered it before.

Here's the deal - he modeled a spring with a simple helical sweep and then inserted it into his assembly to mate it in the bore of a corresponding part. He did NOT create an axis in the spring. He turned on the View Temporary Axes toggle and one appeared in his spring model. He tried to select it in order to mate it concentric with the bore in the other part and was unable to select it. It's on the screen but will NOT select when clicked on (in either the assembly or the part model itself).

Me, I always create a genuine axis and never use the temporary ones so, of course, I just had him create a genuine axis and that finished the problem but it got me curious. I don't think I've ever paid attention to whether or not this has happened before. I know that the software generates temporary axes for cylindrical, conical and toroidal solids and surfaces. So, I did some digging, found a forum post from mid-2017 (   ) where another fellow presented a similar scenario, but the discussion drifted away from whether or not this particular temporary axis was even possible or not.

So, I guess my question is: I need a sanity check on this - is the temporary axis on the helical sweep a "half-implementation" (displayable but not selectable) or is it a regression error, something that has been there and now stopped working (BTW, It's SW2017 SP4.1), or is it local to his machine (and by extension, mine)?

Anyhow, I'd sure appreciate your input, if only to satisfy my curiosity.

Cheers,

Eric

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