I’d guess that v6 introduced click select as an alternative way to the traditional hover+key select (operation) mode in order to allow more people to use Kicad. Indeed, hover+key is not common, but exceptionally efficient.
The problem with the alternative operation mode (in Schematic & Layout) is as follows:
When I do traditional hover, e.g. with M, then the moved object is no longer selected and when I then move another object: no quirks. However, when an object is (e.g. accidentally) selected by click, then upon termination of the move, the object is still selected. With my habit of hover+hotkey of the next object, the still-selected object is being moved…
It would be very helpful if the traditional hover technique of edit operations does not suffer of drawbacks due to the introduction of a click mode.
Those who do not use the hover technique encounter no problems. If the next object is selected, then the previous object is automatically deselected.
I think that some thorough thinking about improving these important handling details would open the door to a solution that is satisfiable for everybody.
A preferences setting could be an alternative (e.g. “hover only” operations start)
The preferences option “First hotkey selects tool” (hint found in another posting) seems not to make any difference (v7.0.6).