Line objects are not rendered in Legend Designer when using Line theme template in MapInfo Pro

Product affected: MapInfo Pro (all versions)
 

Issue

Line objects are not rendered in Legend Designer when using Line thematic template in MapInfo Pro:

User-added image

Cause

Theme Templates use the Dominant object type in the table to decide how to render themes.
So if a user has a mixed table of Lines\Plines and Polygons and there are more Polygons than Lines\Plines in the table, that is how the theme will be rendered.
This is working as designed since Theme templates have been introduced in MapInfo Pro v5.x.
 

Resolution

UPDATED: July 2, 2020
Please separate the object types into two tables. One table per object type.