invalidateLayout method
If #isOngoing is true and if an initial layout has not yet been performed, set the #isValidLayout property to false, and ask to perform another layout in the near future. If #isInitial is true, this layout is invalidated only when the Diagram#model is replaced, not under the normal circumstances such as when parts are added or removed or due to other calls to Layout#invalidateLayout.
If you set both #isInitial and #isOngoing to false, there will be no automatic layout invalidation, because this method will not set #isValidLayout to false. However you can still set #isValidLayout explicitly.
This is typically called when a layout property value has changed, or when a Part is added or removed or changes visibility, if Part#layoutConditions includes the pertinent flags.
Implementation
void invalidateLayout() {
_i4.callMethod(
this,
'invalidateLayout',
[],
);
}