A single SCH_COMMIT::Push fires OnItemsAdded/Removed/Changed separately and
synchronously, then RecalculateConnections once. COLLAB_LISTENER emitted each
category as its own delta, so the peer applied one atomic edit as three separate
commits, each with its own connectivity recompute. On a large connected drag the
junction at the wires' new crossing (added) was applied before the wires moved
(changed) -> dangling junction -> the peer's cleanup deleted it (lost segments).
COLLAB_LISTENER now buffers added/changed/removed (serialized in each synchronous
callback) and flushes one combined delta after Push returns, coalesced via
CallAfter. doApply applies it atomically removed->changed->added in a single
commit with one recompute, so the junction survives. Verified two-tab: a G-drag
of U1A that previously left the peer at 74 items / 7 junctions now emits one
delta {a:1,c:4,r:1} and both tabs converge at 75 / 8.
Root-repo only; kicad and wxwidgets untouched.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>