The Select tool

Click an object or draw a box around it to create a mask, then refine the selection with further clicks.

Choose Select in the tool row at the bottom of Layers. It works even when the survey has not detected a named object.

Click to include missed areas. ⌥-click to exclude areas. Initial selection takes about a tenth of a second, with refinements usually faster. Each click is one undo step.

A shape supports twelve refinements. At the limit, finish it and create another shape in the same layer. Press ⏎, Done or esc to finish. Closing or changing tools, or selecting another layer, also finishes it. The next click starts a new shape.

See Repairing a photograph.