Summary: Let users click a metric's legend entry to toggle it on or off in the chart. The choice should persist (not vanish when the cursor moves) and support multiple selections.
Why this matters: When a chart has 4–6 metrics (e.g., Revenue, Cost, Margin, Forecast, Budget, Actuals), users frequently want to focus on a subset, without rebuilding the visualization or duplicating it. Today, this isn't possible in OAC without editing the viz itself.
Current limitation: The only way to isolate a metric today is to hover over it, which:
- Only highlights one metric at a time (can't compare two of five)
- Disappears the moment the cursor moves — no persistence
- Doesn't communicate state, so users can't tell what's "on" vs "off"
Proposed behavior:
- Click a legend entry → that metric fades (or hides) in the chart
- Click again → it returns
- The legend entry shows clear visual state (e.g., struck-through or dimmed) so users know what's active
- Works across line, bar, area, and combo charts
Precedent: This is a standard pattern in Tableau, Power BI, Excel charts, and most JavaScript charting libraries (Chart.js, Highcharts, ECharts). Users coming from those tools expect it and are surprised it doesn't work in OAC.
Business value: Faster exploratory analysis, fewer duplicate visualizations, and a smoother experience for business users who don't want to enter edit mode to temporarily hide a series.
