When new variables are added to the central panel, they arrive at a random location, including slightly off the visible screen, and quickly settle nicely into the central cluster of variables due to the attractive and repulsive tensions in the force-directed layout.
However, when the central panel is pinned, then pebbles stay in place and ignore the forces that make the pebble movement dynamic. Thus a new variable being added can arrive in a poor location and remain there, including, right on top of other pebbles, or even worse, off screen.
They should instead maybe turn up in some empty available visible space.
When new variables are added to the central panel, they arrive at a random location, including slightly off the visible screen, and quickly settle nicely into the central cluster of variables due to the attractive and repulsive tensions in the force-directed layout.
However, when the central panel is pinned, then pebbles stay in place and ignore the forces that make the pebble movement dynamic. Thus a new variable being added can arrive in a poor location and remain there, including, right on top of other pebbles, or even worse, off screen.
They should instead maybe turn up in some empty available visible space.