This can either be fixed via a widget, or treated as a bug.

What if it's a mobile unit? Rightclick something coming from out of range so it gets worked on ASAP when it comes into range

Could it be made so the command persists even when out of range, meanwhile assisting other nearby jobs?

While I agree this is often problematic behaviour, it’s also very useful to be a able to quickly and easily tell all constructors to drop what they’re doing and allocate all buildpower & resources to That One Urgent Thing.

Some alternate way to juggle build target priority and resource allocation that doesn’t require tracking down every single last builder & con turret would be valuable - even if that looks like:

1. select all construction turrets
2. set all construction turrets on wait
3. command all construction turrets to assist high-priority build target; order will be blocked for all con turrets not in range, so they will remain on wait, while in-range con turrets would build the high-priority target.

(even better with my conditional wait widget, which will release the turrets from waiting as soon as the high priority build target is complete)

Providing resource allocation isn’t a concern with repairing mobile units, so sprEEEzy’s suggestion for that case seems adequate.

Where this becomes extra problematic is when you're reclaiming buildings that are far from most turrets. You can't tell which ones can reach, so you select most of them. 3-4 reclaim, rest stay idle. You float metal after the reclaim is done because metal wasn't being spent during the reclaim.

Ideally, you'd want to mirror "Set Target" behavior of combat units; but for con turret assisting.

Always bugged me, but I had workaround, I just select nanos that can have the range with a selector like this ->
bind YOURBUTTON select FromMouse_380+_AbsoluteHealth_559_Not_AbsoluteHealth_561_Not_IdMatches_cormmkr+_ClearSelection_SelectAll+