Problem

When all values in a chart are 0 (e.g., no blocking events or deadlocks in the time range), the chart appears completely empty — no line, no markers, just blank space with a collapsed Y-axis. This makes it look like the chart is broken rather than showing that the signal is present but at zero.

Expected Behavior

A flat line at 0 should be visible. Zero is still a data point — it tells you the collector is running and nothing is happening, which is different from "no data."

Affected Charts

• Locking > Trends: Blocking Events, Blocking Duration, Deadlock Count, Deadlock Wait Time
• Likely affects other charts with the same LockChartVerticalAxis behavior when all values are 0

Root Cause

LockChartVerticalAxis calls chart.Plot.Axes.GetLimits() and locks the Y-axis to those limits. When all values are 0, the limits collapse to 0-0, making the line invisible.

Fix

When the Y range is 0 (all values equal), set a minimum Y range (e.g., 0 to 1) so the flat line is visible.