Spotfire: Trellis is ignored when lines are added from data table

Problem:
When adding a horizontal line from a secondary data table to a trellised line chart, the line does not respect the trellis configuration, resulting in all reference lines being displayed across every panel.

Consider the following scenario:

• Visualization: A line chart created from a data table Test value, trellised by a column Test name.
• Added Reference: A horizontal line added using values from a separate data table, Reference range.

Result:

• Expected: A single, relevant reference line should appear in each trellis panel.
• Actual: Multiple lines (representing all Test name values) are displayed across every trellis panel.

Screenshot of the "actual result":

Resolution:
To ensure the horizontal lines respect the trellis settings, you must define a data relation (Data > Data table properties > Relations) between the two data tables. In this scenario, column Test name should be used as the key column.

Screenshot of the Data table Relation dialog:

Screenshot of the "expected result":