Add Reference Line Based on Constant Secondary Y-Axis Value for Visualizations

I propose adding an option to include a reference line based on a constant secondary y-axis value for visualizations that support a secondary y-axis, such as line charts and line + stacked/clustered column charts. This feature would enhance the analytical capabilities of these visualizations by allowing users to easily compare data points against a fixed benchmark or target value on the secondary y-axis.

Benefits:

1. Improved Data Analysis: Users can quickly identify how data points relate to a specific benchmark or target value, facilitating better decision-making.
2. Enhanced Visualization: Adding a reference line provides a clear visual cue, making it easier to interpret complex data sets.
3. Flexibility: This feature would be useful across various scenarios, such as financial analysis, performance tracking, and scientific research, where secondary y-axis values are commonly used.

Implementation:

• Users can input a constant value for the secondary y-axis reference line.
• The reference line should be customizable in terms of color, style, and label to fit different visualization needs.
• This option should be available in visualizations that support secondary y-axis functionality such as line charts and line + stacked/clustered column charts.
• Functionality would match that of the existing constant lines for x-axis and y-axis in the Reference Line section of the Format pane.

By incorporating this feature, Microsoft Power BI can further empower users to create more insightful and actionable visualizations.