Issue #10688 reports
[Bug]: Sampler preview disappears when switching tabs or applicationsMirror 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 → ...