The source of the source is equal to the source of the target.

[RamonAbudAlcala]

When drawing an n-cell for n>1 one usually needs to re-draw the source/target of the cell that is saved with the "source" or "target" button.

It would be nice for example if after clicking "source" and the "saved source" has dimension >1 then globular asks for the source or the target to be redrawn (or to have a clear canvas). This will save some time of everyone's life.