Should subjects be selected before, during, or after creating a regulator?
Right now, to create an inversive distance regulator, you first select two elements and then activate the inversive distance regulator tool using a button or keyboard shortcut. If you have the wrong number of elements selected, the button and shortcut are disabled.
Another possible workflow would be to first activate the inversive distance regulator tool and then to select two elements.
We could also imagine a hybrid workflow where the inversive distance regulator creation tool, when activated, watches the size of the selection, creating a regulator as soon as the size of the selection reaches exactly two. If the selection is ordered, the tool could create a regulator as soon as the size of the selection reaches at least two, using the first two selected elements as subjects.
Should actions consume the selection?
Before pull request #138, adding an inversive distance regulator would clear the selection. When we introduced the action system in commit #138, this convention got trickier to implement, so we dropped it. We should think about whether we actually want it. If we do, maybe we should introduce a general way to configure a parametric action so that if its parameter is read from the selection, it will clear the selection when it runs.
Should the selection be ordered?
To support regulators whose subjects are ordered, like a signed volume regulator for a quadruple of points, we may need to give the selection an order too.