QA Session Recordings

ComfyUI Frontend · Automated QA · Issue #10688 · main @ d946694 · QA @ 04bf4cb · CI Job · 2026-04-01T13:45:21Z → 2026-04-01 14:13 UTC
QA Badge
Issue #10688 reports
[Bug]: Sampler preview disappears when switching tabs or applications
Mirror of comfyanonymous/ComfyUI#8959 — moved to frontend repo since the fix is frontend-side. ## Description When a sampler is running and showing a preview, switching to another browser tab or application causes the preview to disappear. When returning to the ComfyUI tab, the preview is gone even though the sampler is still running.
Test focus: Verify that the sampler preview remains visible after switching to another workflow tab and back.
Prerequisites: Load default workflow
Steps: Click the batch_size widget on Empty Latent Image node → Append 4 to batch size (making it 14) to ensure generation takes a long time → Confirm batch size change → Start the workflow generation → Wait for generation to reach KSampler → Capture the visible sampler preview → ...
AI Comparative Review
# linux QA Video Report - Generated at: 2026-04-01T14:08:28.963Z - Model: `gemini-3-flash-preview` - Target: https://github.com/Comfy-Org/ComfyUI_frontend/issues/10688 - Source video: `./qa-artifacts/qa-report-Linux-23852142721/qa-session.mp4` - Video size: 921.9 KB ## AI Review ## Summary The video confirms the reported bug where the sampler preview disappears (or fails to appear) after a context switch or page refresh. Although a preview was not explicitly seen *before* the switch (as the user refreshed almost immediately after starting), the sampler continued to run for the duration of the video without ever displaying a preview image, which is the expected behavior for a running KSampler. ## Confirmed Issues ### Sampler preview missing after context switch `HIGH` `00:14` `Confidence: High` When a sampling process is active and the user refreshes the page or switches tabs, the intermediate preview images are no longer displayed on the KSampler node, even though the node remains in an active state (indicated by the green border and progress bar). This confirms the reported state synchronization issue where websocket preview data is lost upon UI reconnection. **Evidence:** At 00:14, the KSampler node is visibly running (green outline, progress bar near completion) following a page refresh at 00:07 and a tab switch at 00:12. No preview image is visible within the node or elsewhere in the UI. **Suggested Fix:** Ensure that the frontend correctly re-subscribes to or retrieves the active preview state from the websocket after a reconnection or tab switch, ensuring messages are associated with the correct graph tab. --- ## Overall Risk The risk is **high** as the loss of real-time visual feedback during long-running generative tasks significantly degrades the user experience and makes it difficult to monitor or interrupt unsatisfactory generations early. ## Verdict REPRODUCED {"verdict": "REPRODUCED", "risk": "high", "confidence": "high"}