[Plots] Creating a plot with telemetry on axes 2 and 3 only shows no data.

[akhenry]

Summary

A plot with telemetry on axes 2 and 3, but with nothing on axis 1 shows no data at all. The axes continue scaling etc. but no data is plotted.

Expected vs Current Behavior

I think the expected behavior here is open to debate. Two potential solutions:

1. We just fix the bug that is preventing the data showing and allow users to plot on axes 2 and 3 with nothing on 1. Although this configuration doesn't make much sense, it might be the simplest to implement. OR
2. Higher order axes are only "unlocked" when lower order axes are populated. The implementation of this will be complex because we will have to "reshuffle" axes in the event that someone removes the last object from a lower-order axis.

On balance, my preference is for 1.

Steps to Reproduce

1. Create a new Overlay Plot
2. Drag two telemetry points into the plot.
3. They will be mapped to axis 1 by default
4. In the elements pool, drag one of the telemetry points to axis 2.
5. Drag the remaining telemetry point to axis 3
6. Observe that historical data remains in the plot but no new data is shown. Navigating away and back will result in an empty plot.

Environment

• Open MCT Version: 2.1.6
• Deployment Type: VIPER test

Impact Check List

• Data loss or misrepresented data?
• Regression? Did this used to work or has it always been broken?
• Is there a workaround available?
• Does this impact a critical component?
• Is this just a visual bug with no functional impact?
• Does this block the execution of e2e tests?
• Does this have an impact on Performance?

[ozyx]

This happens if Y Axis 1 is empty regardless of whether the telemetry is plotted on Axis 2, 3 or both

[ozyx]

Testing Instructions

1. Create an Overlay Plot
2. Drag a few telemetry objects into it
3. In edit mode, in the elements pool, drag all of the telemetry off of Y Axis 1 and onto 2 or 3
4. Click save and finish
5. Navigate away, navigate back
6. Verify that all telemetry plots correctly and correct YAxes are shown
7. Verify no errors in the console
8. In realtime mode, verify that new data continues to be plotted

[akhenry]

Verified fixed! Nice work for turning this around so quickly.

[jvigliotta]

Verified Fixed - Testathon 1/31/23