Load styles does not override document styles

I create a new document from a plain text document then want to apply styles from another document or from a template.

When I ‘load styles’, I expect those loaded styles to override such styles as ‘default’. But this does not happen.

How can I force the document to override the initial styles with the imported styles? Or perhaps I misunderstand something?

Very recently I wrote and tested user code for loading (and overwriting) styles, and it worked as expected. This was with V6.1 (6.1.1 or 6.1.2).
What version do you use? (Always give information that may be relevant.)
First of all tell what you actually tried step by step.

Version: 6.0.6.2
Build ID: 1:6.0.6-0ubuntu0.18.04.1
CPU threads: 4; OS: Linux 4.15; UI render: default; VCL: gtk3;
Locale: en-CA (en_CA.UTF-8); Calc:

Styles Dialog / Load Styles/ Select Template Name

To document the steps for you I just went through again and this time I checked all the load options including ‘overwrite’ . That has done the trick. Thanks for sending me on that adventure.

(Just to mark this question as answered:)

The answer was given by the OP in his comment on the question: “…I just went through again and this time I checked all the load options including ‘overwrite’ . That has done the trick.”