Function note_layout_moved 

pub fn note_layout_moved()

From a widget’s update: an animation of its own moved or resized what it lays out (a glide, a jump in progress, a give springing back, a pane gliding open, a reveal growing a pill), so the last layout no longer stands. The host lays the window out again in this frame; it is no change of the model, and nothing syncs.

A frame only an animation asked for is otherwise only drawn: an animation that moves nothing it lays out (a spinner, a fade, a pose applied as a draw transform) costs a paint, not a layout and a republication of the app’s actions. A widget whose animation moves layout calls this on every frame it runs, including the one it lands on.