fix(studio): stop a group drag from jumping, and commit it in one request - #3134
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miguel-heygen merged 2 commits intoAug 9, 2026
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Dragging several elements at once and dropping them made one of them snap back to where it started for a frame or two, then jump forward again. Each member of the group is written separately, and every write patched the live GSAP tween in place and then seeked the player. A seek re-renders the WHOLE timeline, not the tween that changed, so the members still queued behind that write got repainted from their un-patched tweens: back to their pre-drag position, where they sat until their own write landed. Only members whose tween actually renders at the playhead showed it, which is why a group of three flashed one element and left the others still. The group commit now defers the seek for every member but the last, so the queued members keep the transform the gesture left on them and the whole group repaints once, from the fully patched timeline.
Dragging N elements cost N writes and 9 reads for a three-element group: each member fetched the composition's parse to preflight, fetched it again to resolve its tween, then wrote the file on its own round trip. Every one of those writes re-read, re-parsed and re-serialized the whole composition. Three changes, same behaviour: - The parse endpoint shares an in-flight request per file, so callers asking for the same composition at the same moment get one request. Only overlapping calls share — the entry is dropped as soon as it settles, so a read after a write still gets a fresh parse. - The group preflight runs its members together instead of one at a time. A preflight writes nothing, so there is nothing to order. - Members' mutations are queued and sent as one batch write. Anything that re-reads the file flushes the queue first, so a member resolving a shared or stale tween never reads a composition missing writes it is about to build on. The batch carries each member's runtime patch, and only the last one re-renders. A three-element group drag now issues 2 reads and 1 write, down from 9 and 3.
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What
Dragging a group no longer makes one member snap back to its starting position for a frame, and the whole group is saved in one request instead of one per member.
Why
Each member of a group was written separately, and every write patched the live GSAP tween in place and then seeked the player. A seek re-renders the whole timeline, not the tween that changed, so members still queued behind that write got repainted from their un-patched tweens — back to their pre-drag position, where they sat until their own write landed.
Separately, a three-element drag cost 3 writes and 9 parse reads, each write re-reading and re-serializing the whole composition.
How
The group commit defers the seek for every member but the last, so queued members keep the transform the gesture left on them and the group repaints once from the fully patched timeline. Mutations are queued and sent as one batch write; anything that re-reads the file flushes the queue first, so a member resolving a shared or stale tween never reads a composition missing writes it is about to build on. The parse endpoint shares an in-flight request per file.
Test plan
Seventh of eight stacked PRs re-cutting #3077.