Fix dashboard UI freezing with batched updates and deferred callbacks #597
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Address performance issues where the dashboard UI partially freezes and only unfreezes when switching desktops. The root causes were unbatched widget updates and rendering all tabs simultaneously. Key fix: - Add dynamic=True to PlotGridTabs, so Panel only renders the visible tab instead of all tabs simultaneously. This was the primary cause of 3-5 second lag when changing grid settings. Additional fixes: - Add pn.io.hold() to PlotConfigModal wizard initialization and cascade handlers (_initialize_selections, _on_namespace_change, _on_workflow_change) - Prevent redundant _update_preview() calls in PlotGridManager by adding a suppression flag during batch operations - Replace 1ms periodic callback hack with pn.state.execute() for deferred plot insertion - Add pn.io.hold() to ConfigurationWidget._on_aux_source_changed() See docs/developer/plans/dashboard-ui-freezing-investigation.md for detailed analysis of the issue. Prompt: I need your help investigating some serious performance issues I see when running the dashboard when I have multiple tabs with plot grids. The UI often partially freezes, not reacting to clicks or changes - but then switching to a different desktop and back again suddenly unfreezes.
When subscribing to a workflow that already has data, the callback chain previously ran synchronously: subscribe_to_workflow() → on_job_available() → setup_data_pipeline() → register_subscriber() → trigger() → on_first_data() → create_plot(), all blocking the UI until complete. Now on_first_data is deferred using pn.state.execute(), allowing the subscription to return immediately and plot creation to happen on the next event loop iteration.
Instead of deleting and recreating all cell widgets on each click, update existing button properties in-place. This avoids the overhead of Panel widget creation (event binding, DOM manipulation, etc.). Changes: - Add CellAppearance dataclass to hold computed styling properties - Add _compute_cell_appearance() to extract styling computation - Store button references in _cell_buttons dict for fast updates - Add _update_cell_in_place() to modify button properties directly - Simplify _refresh_all_cells() to use in-place updates Prompt: The mechanism in PlotGrid that updates cells after clicking is very slow - sometimes takes a couple of seconds. Any ideas of how to make it better? 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
nvaytet
approved these changes
Dec 8, 2025
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Is it correct that apart from adding with pn.io.hold(), only indentation has changed in this file?
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Summary
dynamic=Trueto PlotGridTabs, so Panel only renders the visible tab instead of all tabs simultaneously. This was the primary cause of 3-5 second lag when changing grid settings. It is likely also responsible for avoiding total freezes, but we will not to monitor this more in the future.on_first_datacallback usingpn.state.execute()to break synchronous callback chains that blocked the UI during plot creation.pn.io.hold()batching to PlotConfigModal wizard initialization, cascade handlers, and ConfigurationWidget to reduce render cycles.Closes #575
🤖 Generated with Claude Code