Rounding a single corner is done by selecting that corner, then
dragging its widget: a drag on a path selected whole rounds every
corner with both tools, as before. What was missing is selecting the
corner on the widget itself. With the Direct Selection tool a plain
click on a corner widget (press and release, no drag) now selects that
corner, as a click on the corner's anchor does; Shift-click toggles it.
The widget is then the only one showing, and the next drag on it rounds
that corner alone.
Unchanged: Alt-click cycles the corner kind, the Selection tool's click
on a widget does nothing, corners picked by their anchors edit together.
Test: corners::tests::a_click_on_a_widget_with_direct_selection_selects_its_corner.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>