base.mp4: Web dev app at base d6d1763d415c59735708036ab790c540ef962cf0; Linux browser panel; 1440x900 CSS pixels; dark appearance; fresh isolated database, automatic seeding disabled; synthetic Replay todo-list parent and /side Check the sample task. No completion toast while New thread is visible and focused.
head.mp4: Same environment and interaction at head 6142cf4080261614db48e2bf708322f640084293. Side chat completed toast identifies Check the sample task.
base-visible.mp4: Base, same browser/viewport/theme/seed as above. Existing side chat receives Check the sample task again while its parent's right panel stays visible. Completion appears in the conversation; no toast.
head-visible.mp4: Head, same browser/viewport/theme/seed and visible-panel follow-up as base-visible.mp4. Completion appears in the conversation; no toast.
head-open.mp4: Head, same browser/viewport/theme. Additional follow-up in the synthetic side chat, navigate to New thread, click completion toast's Open thread. Parent route opens with the completed side chat selected. This is supplemental navigation evidence, after the matched pair and visible-panel controls; it contains additional synthetic follow-up turns.
Videos use synthetic data only. Environment label is masked in main and navigation clips. No tests are offered as evidence. AI-assisted; verified with the tools listed above.