adjustmentListener
Runs onAdjustment whenever a scrollbar's value changes - the scrollbars adjustmentListener lists.
onAdjustment is read when the event fires, so writing a fresh lambda on every recomposition registers nothing again.
Return
this chain with the adjustment callback declared on it.
Parameters
receives the event, whose value is the scrollbar's current value and whose valueIsAdjusting is true while the user is still dragging the knob.
See also
Attaches an AdjustmentListener (addAdjustmentListener/removeAdjustmentListener) to a scrollbar (javax.swing.JScrollBar, java.awt.Scrollbar).
A scroll pane's own position is hoistable state (ScrollState); this builder is for a scrollbar a custom component drives itself.
Return
this chain with the adjustment listener declared on it.
Parameters
attached by identity, so a remembered instance stays put while a fresh one on every pass is detached and re-added.